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Bicaldo IEC, Padilla KSAR, Tu TH, Chen WT, Mendoza-Pascual MU, Vicera CVB, de Leon JR, Poblete KN, Austria ES, Lopez MLD, Kobayashi Y, Shiah FK, Papa RDS, Okuda N, Wang PL, Lin LH. The methane-oxidizing microbial communities of three maar lakes in tropical monsoon Asia. Front Microbiol 2024; 15:1410666. [PMID: 39044952 PMCID: PMC11263035 DOI: 10.3389/fmicb.2024.1410666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/21/2024] [Indexed: 07/25/2024] Open
Abstract
Methane-oxidizing bacteria (MOB) is a group of planktonic microorganisms that use methane as their primary source of cellular energy. For tropical lakes in monsoon Asia, there is currently a knowledge gap on MOB community diversity and the factors influencing their abundance. Herewith, we present a preliminary assessment of the MOB communities in three maar lakes in tropical monsoon Asia using Catalyzed Reporter Deposition, Fluorescence In-Situ Hybridization (CARD-FISH), 16S rRNA amplicon sequencing, and pmoA gene sequencing. Correlation analysis between MOB abundances and lakes' physicochemical parameters following seasonal monsoon events were performed to explain observed spatial and temporal patterns in MOB diversity. The CARD-FISH analyses detected the three MOB types (I, II, and NC10) which aligned with the results from 16S rRNA amplicons and pmoA gene sequencing. Among community members based on 16S rRNA genes, Proteobacterial Type I MOB (e.g., Methylococcaceae and Methylomonadaceae), Proteobacterial Type II (Methylocystaceae), Verrucomicrobial (Methylacidiphilaceae), Methylomirabilota/NC10 (Methylomirabilaceae), and archaeal ANME-1a were found to be the dominant methane-oxidizers in three maar lakes. Analysis of microbial diversity and distribution revealed that the community compositions in Lake Yambo vary with the seasons and are more distinct during the stratified period. Temperature, DO, and pH were significantly and inversely linked with type I MOB and Methylomirabilota during stratification. Only MOB type I was influenced by monsoon changes. This research sought to establish a baseline for the diversity and ecology of planktonic MOB in tropical monsoon Asia to better comprehend their contribution to the CH4 cycle in tropical freshwater ecosystems.
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Affiliation(s)
- Iona Eunice C. Bicaldo
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
| | - Karol Sophia Agape R. Padilla
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Philippine Genome Center, University of the Philippines, Quezon City, Philippines
- Department of Science and Technology, Science Education Institute, Taguig, Philippines
| | - Tzu-Hsuan Tu
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
- Department of Oceanography, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Wan Ting Chen
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
| | - Milette U. Mendoza-Pascual
- Department of Environmental Science, School of Science and Engineering, Ateneo Research Institute for Science and Engineering, Ateneo de Manila University, Quezon City, Philippines
| | | | - Justine R. de Leon
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
- Department of Biological Sciences, University of Santo Tomas, Manila, Philippines
| | | | | | - Mark Louie D. Lopez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Yuki Kobayashi
- Center for Ecological Research, Kyoto University, Shiga, Japan
| | - Fuh-Kwo Shiah
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - Rey Donne S. Papa
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
- Department of Biological Sciences, University of Santo Tomas, Manila, Philippines
| | - Noboru Okuda
- Center for Ecological Research, Kyoto University, Shiga, Japan
- Research Center for Inland Seas, Kobe University, Kobe, Japan
- Research Institute for Humanity and Nature, Kamigamo Motoyama, Kita Ward, Kyoto, Japan
| | - Pei-Ling Wang
- Institute of Oceanography, National Taiwan University, Taipei, Taiwan
- Research Center for Future Earth, National Taiwan University, Taipei, Taiwan
| | - Li-Hung Lin
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
- Research Center for Future Earth, National Taiwan University, Taipei, Taiwan
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2
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Carmichael MJ, Martinez M, Bräuer SL, Ardón M. Microbial Communities in Standing Dead Trees in Ghost Forests are Largely Aerobic, Saprophytic, and Methanotrophic. Curr Microbiol 2024; 81:229. [PMID: 38896154 PMCID: PMC11186919 DOI: 10.1007/s00284-024-03767-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024]
Abstract
Standing dead trees (snags) are recognized for their influence on methane (CH4) cycling in coastal wetlands, yet the biogeochemical processes that control the magnitude and direction of fluxes across the snag-atmosphere interface are not fully elucidated. Herein, we analyzed microbial communities and fluxes at one height from ten snags in a ghost forest wetland. Snag-atmosphere CH4 fluxes were highly variable (- 0.11-0.51 mg CH4 m-2 h-1). CH4 production was measured in three out of ten snags; whereas, CH4 consumption was measured in two out of ten snags. Potential CH4 production and oxidation in one core from each snag was assayed in vitro. A single core produced CH4 under anoxic and oxic conditions, at measured rates of 0.7 and 0.6 ng CH4 g-1 h-1, respectively. Four cores oxidized CH4 under oxic conditions, with an average rate of - 1.13 ± 0.31 ng CH4 g-1 h-1. Illumina sequencing of the V3/V4 region of the 16S rRNA gene sequence revealed diverse microbial communities and indicated oxidative decomposition of deadwood. Methanogens were present in 20% of the snags, with a mean relative abundance of < 0.0001%. Methanotrophs were identified in all snags, with a mean relative abundance of 2% and represented the sole CH4-cycling communities in 80% of the snags. These data indicate potential for microbial attenuation of CH4 emissions across the snag-atmosphere interface in ghost forests. A better understanding of the environmental drivers of snag-associated microbial communities is necessary to forecast the response of CH4 cycling in coastal ghost forest wetlands to a shifting coastal landscape.
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Affiliation(s)
- Mary Jane Carmichael
- Departments of Biology and Environmental Studies, Hollins University, Roanoke, VA, 24020, USA.
| | - Melinda Martinez
- U.S. Geological Survey, Eastern Ecological Science Center, Laurel, MD, 20708, USA
| | - Suzanna L Bräuer
- Department of Biology, Appalachian State University, Boone, NC, 28608, USA
| | - Marcelo Ardón
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA
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Mei C, Shi Y, Wang Y, Qiu Z, Yang H. Termitidicoccus mucosus gen. nov. sp. nov. a novel Verrucomicrobiota species isolated from Reticulitermes chinensis gives insights of high adaptability of symbiotic bacteria to termite gut ecosystem. Res Microbiol 2024; 175:104173. [PMID: 38157920 DOI: 10.1016/j.resmic.2023.104173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 10/27/2023] [Accepted: 12/07/2023] [Indexed: 01/03/2024]
Abstract
Verrucomicrobiota is widely distributed in various habitats including insect guts. It was found to be prevalent in almost all investigated termite guts, whereas their physiological functions are not very clear. In this study we characterized the physiological and genomic properties of Verrucomicrobiota strain TSB47T isolated from Reticulitermes chinensis. The cells of strain TSB47T were Gram-stain-negative, non-motile, and non-spore-forming coccoid with one or more warts. 16S rRNA gene analysis showed that the closest relatives of strain TSB47T were Opitutaceae strain TAV1 and Ereboglobus luteus Ho45T (98.3% and 95.4% sequence similarity, respectively). Whole genome analysis revealed that there are a large number of glycoside hydrolase genes, amino acid metabolism genes, complete Mo-Fe nitrogenase and Fe-Fe nitrogenase gene clusters, as well as cbb3-type cytochrome oxidase gene in the genome of strain TSB47T. Strain TSB47T grows well under anaerobic and microaerophilic conditions with a strong tolerance to oxygen. Physiological and genomic characters of strain TSB47T indicated its high adaptability to termite gut ecosystem. Based on phenotypic and phylogenetic evidence, we suggest strain TSB47T as the type species of a novel genus in the family Opitutaceae, for which the name Termitidicoccus mucosus sp. nov. is proposed. The type strain is TSB47T (CCTCC AB2022447T; KCTC 102044T).
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Affiliation(s)
- Cheng Mei
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Yu Shi
- College of Food and Biotechnology, Wuhan Institute of Design and Sciences, Wuhan 430079, PR China
| | - Yu Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Zhengyong Qiu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Hong Yang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China.
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Patil SK, Islam T, Tveit A, Hodson A, Øvreås L. Targeting methanotrophs and isolation of a novel psychrophilic Methylobacter species from a terrestrial Arctic alkaline methane seep in Lagoon Pingo, Central Spitsbergen (78° N). Antonie Van Leeuwenhoek 2024; 117:60. [PMID: 38517574 PMCID: PMC10959801 DOI: 10.1007/s10482-024-01953-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 02/19/2024] [Indexed: 03/24/2024]
Abstract
The microbial diversity associated with terrestrial groundwater seepage through permafrost soils is tightly coupled to the geochemistry of these fluids. Terrestrial alkaline methane seeps from Lagoon Pingo, Central Spitsbergen (78°N) in Norway, with methane-saturated and oxygen-limited groundwater discharge providing a potential habitat for methanotrophy. Here, we report on the microbial community's comparative analyses and distribution patterns at two sites close to Lagoon Pingo's methane emission source. To target methane-oxidizing bacteria from this system, we analysed the microbial community pattern of replicate samples from two sections near the main methane seepage source. DNA extraction, metabarcoding and subsequent sequencing of 16S rRNA genes revealed microbial communities where the major prokaryotic phyla were Pseudomonadota (42-47%), Gemmatimonadota (4-14%) and Actinobacteriota (7-11%). Among the Pseudomonadota, members of the genus Methylobacter were present at relative abundances between 1.6 and 4.7%. Enrichment targeting the methane oxidising bacteria was set up using methane seep sediments as inoculum and methane as the sole carbon and energy source, and this resulted in the isolation of a novel psychrophilic methane oxidizer, LS7-T4AT. The optimum growth temperature for the isolate was 13 °C and the pH optimum was 8.0. The morphology of cells was short rods, and TEM analysis revealed intracytoplasmic membranes arranged in stacks, a distinctive feature for Type I methanotrophs in the family Methylomonadaceae of the class Gammaproteobacteria. The strain belongs to the genus Methylobacter based on high 16S rRNA gene similarity to the psychrophilic species of Methylobacter psychrophilus Z-0021T (98.95%), the psychrophilic strain Methylobacter sp. strain S3L5C (99.00%), and the Arctic mesophilic species of Methylobacter tundripaludum SV96T (99.06%). The genome size of LS7-T4AT was 4,338,157 bp with a G + C content of 47.93%. The average nucleotide identities (ANIb) of strain LS7-T4AT to 10 isolated strains of genus Methylobacter were between 75.54 and 85.51%, lower than the species threshold of 95%. The strain LS7-T4AT represents a novel Arctic species, distinct from other members of the genus Methylobacter, for which the name Methylobacter svalbardensis sp. nov. is proposed. The type of strain is LS7-T4AT (DSMZ:114308, JCM:39463).
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Affiliation(s)
- Shalaka K Patil
- Department of Biological Sciences, University of Bergen, Postboks 7803, 5020, Bergen, Norway.
| | - Tajul Islam
- Department of Biological Sciences, University of Bergen, Postboks 7803, 5020, Bergen, Norway
| | - Alexander Tveit
- Department of Arctic and Marine Biology, The Arctic University of Tromsø, 9037, Tromsø, Norway
| | - Andrew Hodson
- University Centre in Svalbard, 9171, Longyearbyen, Norway
| | - Lise Øvreås
- Department of Biological Sciences, University of Bergen, Postboks 7803, 5020, Bergen, Norway
- University Centre in Svalbard, 9171, Longyearbyen, Norway
- Bjerknes Centre for Climate Research, Jahnebakken 5, 5007, Bergen, Norway
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Tucci FJ, Rosenzweig AC. Direct Methane Oxidation by Copper- and Iron-Dependent Methane Monooxygenases. Chem Rev 2024; 124:1288-1320. [PMID: 38305159 PMCID: PMC10923174 DOI: 10.1021/acs.chemrev.3c00727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Methane is a potent greenhouse gas that contributes significantly to climate change and is primarily regulated in Nature by methanotrophic bacteria, which consume methane gas as their source of energy and carbon, first by oxidizing it to methanol. The direct oxidation of methane to methanol is a chemically difficult transformation, accomplished in methanotrophs by complex methane monooxygenase (MMO) enzyme systems. These enzymes use iron or copper metallocofactors and have been the subject of detailed investigation. While the structure, function, and active site architecture of the copper-dependent particulate methane monooxygenase (pMMO) have been investigated extensively, its putative quaternary interactions, regulation, requisite cofactors, and mechanism remain enigmatic. The iron-dependent soluble methane monooxygenase (sMMO) has been characterized biochemically, structurally, spectroscopically, and, for the most part, mechanistically. Here, we review the history of MMO research, focusing on recent developments and providing an outlook for future directions of the field. Engineered biological catalysis systems and bioinspired synthetic catalysts may continue to emerge along with a deeper understanding of the molecular mechanisms of biological methane oxidation. Harnessing the power of these enzymes will necessitate combined efforts in biochemistry, structural biology, inorganic chemistry, microbiology, computational biology, and engineering.
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Affiliation(s)
- Frank J Tucci
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Amy C Rosenzweig
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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6
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Bedekar AA, Deewan A, Jagtap SS, Parker DA, Liu P, Mackie RI, Rao CV. Transcriptional and metabolomic responses of Methylococcus capsulatus Bath to nitrogen source and temperature downshift. Front Microbiol 2023; 14:1259015. [PMID: 37928661 PMCID: PMC10623323 DOI: 10.3389/fmicb.2023.1259015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023] Open
Abstract
Methanotrophs play a significant role in methane oxidation, because they are the only biological methane sink present in nature. The methane monooxygenase enzyme oxidizes methane or ammonia into methanol or hydroxylamine, respectively. While much is known about central carbon metabolism in methanotrophs, far less is known about nitrogen metabolism. In this study, we investigated how Methylococcus capsulatus Bath, a methane-oxidizing bacterium, responds to nitrogen source and temperature. Batch culture experiments were conducted using nitrate or ammonium as nitrogen sources at both 37°C and 42°C. While growth rates with nitrate and ammonium were comparable at 42°C, a significant growth advantage was observed with ammonium at 37°C. Utilization of nitrate was higher at 42°C than at 37°C, especially in the first 24 h. Use of ammonium remained constant between 42°C and 37°C; however, nitrite buildup and conversion to ammonia were found to be temperature-dependent processes. We performed RNA-seq to understand the underlying molecular mechanisms, and the results revealed complex transcriptional changes in response to varying conditions. Different gene expression patterns connected to respiration, nitrate and ammonia metabolism, methane oxidation, and amino acid biosynthesis were identified using gene ontology analysis. Notably, key pathways with variable expression profiles included oxidative phosphorylation and methane and methanol oxidation. Additionally, there were transcription levels that varied for genes related to nitrogen metabolism, particularly for ammonia oxidation, nitrate reduction, and transporters. Quantitative PCR was used to validate these transcriptional changes. Analyses of intracellular metabolites revealed changes in fatty acids, amino acids, central carbon intermediates, and nitrogen bases in response to various nitrogen sources and temperatures. Overall, our results offer improved understanding of the intricate interactions between nitrogen availability, temperature, and gene expression in M. capsulatus Bath. This study enhances our understanding of microbial adaptation strategies, offering potential applications in biotechnological and environmental contexts.
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Affiliation(s)
- Ashwini Ashok Bedekar
- Energy and Biosciences Institute, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Anshu Deewan
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Sujit S. Jagtap
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - David A. Parker
- Energy and Biosciences Institute, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Shell Exploration and Production Inc., Westhollow Technology Center, Houston, TX, United States
| | - Ping Liu
- Energy and Biosciences Institute, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Shell Exploration and Production Inc., Westhollow Technology Center, Houston, TX, United States
| | - Roderick I. Mackie
- Energy and Biosciences Institute, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Christopher V. Rao
- Energy and Biosciences Institute, Materials Research Laboratory, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, IL, United States
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Awala SI, Gwak JH, Kim Y, Seo C, Strazzulli A, Kim SG, Rhee SK. Methylacidiphilum caldifontis gen. nov., sp. nov., a thermoacidophilic methane-oxidizing bacterium from an acidic geothermal environment, and descriptions of the family Methylacidiphilaceae fam. nov. and order Methylacidiphilales ord. nov. Int J Syst Evol Microbiol 2023; 73. [PMID: 37791995 DOI: 10.1099/ijsem.0.006085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023] Open
Abstract
Strain IT6T, a thermoacidophilic and facultative methane-oxidizing bacterium, was isolated from a mud-water mixture collected from Pisciarelli hot spring in Pozzuoli, Italy. The novel strain is white when grown in liquid or solid media and forms Gram-negative rod-shaped, non-flagellated, non-motile cells. It conserves energy by aerobically oxidizing methane and hydrogen while deriving carbon from carbon dioxide fixation. Strain IT6T had three complete pmoCAB operons encoding particulate methane monooxygenase and genes encoding group 1d and 3b [NiFe] hydrogenases. Simple carbon-carbon substrates such as ethanol, 2-propanol, acetone, acetol and propane-1,2-diol were used as alternative electron donors and carbon sources. Optimal growth occurred at 50-55°C and between pH 2.0-3.0. The major fatty acids were C18 : 0, C15 : 0 anteiso, C14 : 0 iso, C16 : 0 and C14 : 0, and the main polar lipids were phosphatidylethanolamine, aminophospholipid, phosphatidylglycerol, diphosphatidylglycerol, some unidentified phospholipids and glycolipids, and other unknown polar lipids. Strain IT6T has a genome size of 2.19 Mbp and a G+C content of 40.70 mol%. Relative evolutionary divergence using 120 conserved single-copy marker genes (bac120) and phylogenetic analyses based on bac120 and 16S rRNA gene sequences showed that strain IT6T is affiliated with members of the proposed order 'Methylacidiphilales' of the class Verrucomicrobiia in the phylum Verrucomicrobiota. It shared a 16S rRNA gene sequence identity of >96 % with cultivated isolates in the genus 'Methylacidiphilum' of the family 'Methylacidiphilaceae', which are thermoacidophilic methane-oxidizing bacteria. 'Methylacidiphilum sp.' Phi (100 %), 'Methylacidiphilum infernorum' V4 (99.02 %) and 'Methylacidiphilum sp.' RTK17.1 (99.02 %) were its closest relatives. Its physiological and genomic properties were consistent with those of other isolated 'Methylacidiphilum' species. Based on these results, we propose the name Methylacidiphilum caldifontis gen. nov., sp. nov. to accommodate strain IT6T (=KCTC 92103T=JCM 39288T). We also formally propose that the names Methylacidiphilaceae fam. nov. and Methylacidiphilales ord. nov. to accommodate the genus Methylacidiphilum gen. nov.
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Affiliation(s)
- Samuel Imisi Awala
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju 28644, Republic of Korea
| | - Joo-Han Gwak
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju 28644, Republic of Korea
| | - Yongman Kim
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju 28644, Republic of Korea
| | - Chanmee Seo
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju 28644, Republic of Korea
| | - Andrea Strazzulli
- Department of Biology, University of Naples "Federico II", Complesso Universitario Di Monte S. Angelo, Via Cupa Nuova Cinthia 21, 80126, Naples, Italy
| | - Song-Gun Kim
- University of Science and Technology, Yuseong-gu, Daejeon 305-850, Republic of Korea
- Biological Resource Center/ Korean Collection for Type Culture (KCTC), Korea Research Institute of Bioscience and Biotechnology, 181 Ipsingil, Jeongeup-si, Jeollabuk-do, 56212, Republic of Korea
| | - Sung-Keun Rhee
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju 28644, Republic of Korea
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8
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Zhang L, Sun X, Wang L, Zhang H, Chu H, Li Y. Soil edaphic factors and climate seasonality explain the turnover of methanotrophic communities in riparian wetlands. ENVIRONMENTAL RESEARCH 2023; 233:116447. [PMID: 37331554 DOI: 10.1016/j.envres.2023.116447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/08/2023] [Accepted: 06/16/2023] [Indexed: 06/20/2023]
Abstract
Aerobic CH4-oxidizing bacteria (methanotrophs) represent a biological model system for the removal of atmospheric CH4, which is sensitive to the dynamics of water tables. However, little attention has been given to the turnover of methanotrophic communities across wet and dry periods in riparian wetlands. Here, by sequencing the pmoA gene, we investigated the turnover of soil methanotrophic communities across wet and dry periods in typical riparian wetlands that experience intensive agricultural practices. The results demonstrated that the methanotrophic abundance and diversity were significantly higher in the wet period than in the dry period, probably owing to the climatic seasonal succession and associated variation in soil edaphic factors. The co-occurrence patterns of the interspecies association analysis demonstrated that the key ecological clusters (i.e., Mod#1, Mod#2, Mod#4, Mod#5) showed contrasting correlations with soil edaphic properties between wet and dry periods. The linear regression slope of the relationships between the relative abundance of Mod#1 and the carbon to nitrogen ratio was higher in the wet period than in the dry period, whereas the linear regression slope of the relationships between the relative abundance of Mod#2 and soil nitrogen content (i.e., dissolved organic nitrogen, nitrate, and total nitrogen) was higher in the dry period than in the wet period. Moreover, Stegen's null model combined with phylogenetic group-based assembly analysis demonstrated that the methanotrophic community exhibited a higher proportion of drift (55.0%) and a lower contribution of dispersal limitation (24.5%) in the wet period than in the dry period (43.8% and 35.7%, respectively). Overall, these findings demonstrate that the turnover of methanotrophic communities across wet and dry periods were soil edaphic factors and climate dependent.
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Affiliation(s)
- Liyan Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, China
| | - Xiangxin Sun
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Longfei Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, China
| | - Huanjun Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, China
| | - Haiyan Chu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, China.
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9
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Dedysh SN. Describing difficult-to-culture bacteria: Taking a shortcut or investing time to discover something new? Syst Appl Microbiol 2023; 46:126439. [PMID: 37413783 DOI: 10.1016/j.syapm.2023.126439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/17/2023] [Accepted: 06/29/2023] [Indexed: 07/08/2023]
Abstract
Despite the growing interest in isolating representatives of poorly studied and as-yet-uncultivated bacterial phylogenetic groups, these microorganisms remain difficult objects for taxonomic studies. The time required for describing one of these fastidious bacteria is commonly measured in several years. What is even more problematic, many routine laboratory tests, which were originally developed for fast-growing and fast-responding microorganisms, are not fully suitable for many environmentally relevant, slow-growing bacteria. Standard techniques used in chemotaxonomic analyses do not identify unique lipids produced by these bacteria. A common practice of preparing taxonomic descriptions that report a minimal set of features to name a newly isolated organism deepens a gap between microbial ecologists and taxonomists. By contrast, investing time in detailed analysis of cell biology and experimental verification of genome-encoded capabilities of newly isolated microorganisms opens a window for novel, unexpected findings, which may shape our ideas about the functional role of these microbes in the environment.
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Affiliation(s)
- Svetlana N Dedysh
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
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10
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Ratnadevi CM, Erikstad HA, Kruse T, Birkeland NK. Methylacidiphilum kamchatkense gen. nov., sp. nov., an extremely acidophilic and moderately thermophilic methanotroph belonging to the phylum Verrucomicrobiota. Int J Syst Evol Microbiol 2023; 73. [PMID: 37755432 DOI: 10.1099/ijsem.0.006060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023] Open
Abstract
The thermo-acidophilic aerobic methanotrophic Verrucomicrobia bacterium, designated strain Kam1T was isolated from an acidic geothermal mud spring in Kamchatka, Russia. Kam1T is Gram-stain-negative, with non-motile cells and non-spore-forming rods, and a diameter of 0.45-0.65 µm and length of 0.8-1.0 µm. Its growth is optimal at the temperature of 55 °C (range, 37-60 °C) and pH of 2.5 (range, pH 1-6), and its maximal growth rate is ~0.11 h-1 (doubling time ~6.3 h). Its cell wall contains peptidoglycan with meso-diaminopimelic acid. In addition to growing on methane and methanol, strain Kam1T grows on acetone and 2-propanol. Phylogenetically, it forms a distinct group together with other Methylacidiphilum strains and with the candidate genus Methylacidimicrobium as a sister group. These findings support the classification of the strain Kam1T as a representative of a novel species and genus of the phylum Verrucomicrobiota. For this strain, we propose the name Methylacidiphilum kamchatkense sp. nov. as the type species within Methylacidiphilum gen. nov. Strain Kam1T (JCM 30608T=KCTC 4682T) is the type strain.
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Affiliation(s)
| | - Helge-André Erikstad
- Department of Biological Sciences, University of Bergen, P.O. Box 7803, NO-5020 Bergen, Norway
| | - Thomas Kruse
- Department of Biological Sciences, University of Bergen, P.O. Box 7803, NO-5020 Bergen, Norway
- Present address: NORCE, Industrial biotechnology, Prof. Olav Hanssensvei 15, 4021 Stavanger, Norway
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11
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Houghton KM, Carere CR, Stott MB, McDonald IR. Thermophilic methane oxidation is widespread in Aotearoa-New Zealand geothermal fields. Front Microbiol 2023; 14:1253773. [PMID: 37720161 PMCID: PMC10502179 DOI: 10.3389/fmicb.2023.1253773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023] Open
Abstract
Geothermal areas represent substantial point sources for greenhouse gas emissions such as methane. While it is known that methanotrophic microorganisms act as a biofilter, decreasing the efflux of methane in most soils to the atmosphere, the diversity and the extent to which methane is consumed by thermophilic microorganisms in geothermal ecosystems has not been widely explored. To determine the extent of biologically mediated methane oxidation at elevated temperatures, we set up 57 microcosms using soils from 14 Aotearoa-New Zealand geothermal fields and show that moderately thermophilic (>40°C) and thermophilic (>60°C) methane oxidation is common across the region. Methane oxidation was detected in 54% (n = 31) of the geothermal soil microcosms tested at temperatures up to 75°C (pH 1.5-8.1), with oxidation rates ranging from 0.5 to 17.4 μmol g-1 d-1 wet weight. The abundance of known aerobic methanotrophs (up to 60.7% Methylacidiphilum and 11.2% Methylothermus) and putative anaerobic methanotrophs (up to 76.7% Bathyarchaeota) provides some explanation for the rapid rates of methane oxidation observed in microcosms. However, not all methane oxidation was attributable to known taxa; in some methane-consuming microcosms we detected methanotroph taxa in conditions outside of their known temperature range for growth, and in other examples, we observed methane oxidation in the absence of known methanotrophs through 16S rRNA gene sequencing. Both of these observations suggest unidentified methane oxidizing microorganisms or undescribed methanotrophic syntrophic associations may also be present. Subsequent enrichment cultures from microcosms yielded communities not predicted by the original diversity studies and showed rates inconsistent with microcosms (≤24.5 μmol d-1), highlighting difficulties in culturing representative thermophilic methanotrophs. Finally, to determine the active methane oxidation processes, we attempted to elucidate metabolic pathways from two enrichment cultures actively oxidizing methane using metatranscriptomics. The most highly expressed genes in both enrichments (methane monooxygenases, methanol dehydrogenases and PqqA precursor peptides) were related to methanotrophs from Methylococcaceae, Methylocystaceae and Methylothermaceae. This is the first example of using metatranscriptomics to investigate methanotrophs from geothermal environments and gives insight into the metabolic pathways involved in thermophilic methanotrophy.
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Affiliation(s)
- Karen M. Houghton
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Aka Mātuatua | School of Science, Te Whare Wānanga o Waikato | University of Waikato, Hamilton, New Zealand
| | - Carlo R. Carere
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Tari Pūhanga Tukanga Matū | Department of Chemical and Process Engineering, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, New Zealand
| | - Matthew B. Stott
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Kura Pūtaiao Koiora | School of Biological Sciences, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, New Zealand
| | - Ian R. McDonald
- Te Aka Mātuatua | School of Science, Te Whare Wānanga o Waikato | University of Waikato, Hamilton, New Zealand
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Guo K, Glatter T, Paczia N, Liesack W. Asparagine Uptake: a Cellular Strategy of Methylocystis to Combat Severe Salt Stress. Appl Environ Microbiol 2023; 89:e0011323. [PMID: 37184406 PMCID: PMC10305061 DOI: 10.1128/aem.00113-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/17/2023] [Indexed: 05/16/2023] Open
Abstract
Methylocystis spp. are known to have a low salt tolerance (≤1.0% NaCl). Therefore, we tested various amino acids and other well-known osmolytes for their potential to act as an osmoprotectant under otherwise growth-inhibiting NaCl conditions. Adjustment of the medium to 10 mM asparagine had the greatest osmoprotective effect under severe salinity (1.50% NaCl), leading to partial growth recovery of strain SC2. The intracellular concentration of asparagine increased to 264 ± 57 mM, with a certain portion hydrolyzed to aspartate (4.20 ± 1.41 mM). In addition to general and oxidative stress responses, the uptake of asparagine specifically induced major proteome rearrangements related to the KEGG level 3 categories of "methane metabolism," "pyruvate metabolism," "amino acid turnover," and "cell division." In particular, various proteins involved in cell division (e.g., ChpT, CtrA, PleC, FtsA, FtsH1) and peptidoglycan synthesis showed a positive expression response. Asparagine-derived 13C-carbon was incorporated into nearly all amino acids. Both the exometabolome and the 13C-labeling pattern suggest that in addition to aspartate, the amino acids glutamate, glycine, serine, and alanine, but also pyruvate and malate, were most crucially involved in the osmoprotective effect of asparagine, with glutamate being a major hub between the central carbon and amino acid pathways. In summary, asparagine induced significant proteome rearrangements, leading to major changes in central metabolic pathway activity and the sizes of free amino acid pools. In consequence, asparagine acted, in part, as a carbon source for the growth recovery of strain SC2 under severe salinity. IMPORTANCE Methylocystis spp. play a major role in reducing methane emissions into the atmosphere from methanogenic wetlands. In addition, they contribute to atmospheric methane oxidation in upland soils. Although these bacteria are typical soil inhabitants, Methylocystis spp. are thought to have limited capacity to acclimate to salt stress. This called for a thorough study into potential osmoprotectants, which revealed asparagine as the most promising candidate. Intriguingly, asparagine was taken up quantitatively and acted, at least in part, as an intracellular carbon source under severe salt stress. The effect of asparagine as an osmoprotectant for Methylocystis spp. is an unexpected finding. It may provide Methylocystis spp. with an ecological advantage in wetlands, where these methanotrophs colonize the roots of submerged vascular plants. Collectively, our study offers a new avenue into research on compounds that may increase the resilience of Methylocystis spp. to environmental change.
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Affiliation(s)
- Kangli Guo
- Methanotrophic Bacteria and Environmental Genomics/Transcriptomics Research Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Timo Glatter
- Core Facility for Mass Spectrometry and Proteomics, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Nicole Paczia
- Core Facility for Metabolomics and Small Molecule Mass Spectrometry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Werner Liesack
- Methanotrophic Bacteria and Environmental Genomics/Transcriptomics Research Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
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13
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Liu C, Angius F, Pol A, Mesman RA, Versantvoort W, Op den Camp HJM. Identification and characterization of an abundant lipoprotein from Methylacidiphilum fumariolicum SolV. Arch Microbiol 2023; 205:261. [PMID: 37306788 DOI: 10.1007/s00203-023-03603-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/17/2023] [Accepted: 05/30/2023] [Indexed: 06/13/2023]
Abstract
Bacterial lipoproteins are characterized by the presence of a conserved N-terminal lipid-modified cysteine residue that allows the hydrophilic protein to anchor into bacterial cell membranes. These lipoproteins play essential roles in a wide variety of physiological processes. Based on transcriptome analysis of the verrucomicrobial methanotroph Methylacidiphilum fumariolicum SolV, we identified a highly expressed lipoprotein, WP_009060351 (139 amino acids), in its genome. The first 86 amino acids are specific for the methanotrophic genera Methylacidiphilum and Methylacidmicrobium, while the last 53 amino acids are present only in lipoproteins of members from the phylum Verrucomicrobiota (Hedlund). Heterologous expression of WP_009060351 in Escherichia coli revealed a 25-kDa dimeric protein and a 60-kDa tetrameric protein. Immunoblotting showed that WP_009060351 was present in the total membrane protein and peptidoglycan fractions of M. fumariolicum SolV. The results suggest an involvement of lipoprotein WP_009060351 in the linkage between the outer membrane and the peptidoglycan.
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Affiliation(s)
- Changqing Liu
- Faculty of Science, Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Federica Angius
- Faculty of Science, Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Arjan Pol
- Faculty of Science, Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Rob A Mesman
- Faculty of Science, Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Faculty of Science, Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Faculty of Science, Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands.
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14
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Schmitz RA, Peeters SH, Mohammadi SS, Berben T, van Erven T, Iosif CA, van Alen T, Versantvoort W, Jetten MSM, Op den Camp HJM, Pol A. Simultaneous sulfide and methane oxidation by an extremophile. Nat Commun 2023; 14:2974. [PMID: 37221165 DOI: 10.1038/s41467-023-38699-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 05/11/2023] [Indexed: 05/25/2023] Open
Abstract
Hydrogen sulfide (H2S) and methane (CH4) are produced in anoxic environments through sulfate reduction and organic matter decomposition. Both gases diffuse upwards into oxic zones where aerobic methanotrophs mitigate CH4 emissions by oxidizing this potent greenhouse gas. Although methanotrophs in myriad environments encounter toxic H2S, it is virtually unknown how they are affected. Here, through extensive chemostat culturing we show that a single microorganism can oxidize CH4 and H2S simultaneously at equally high rates. By oxidizing H2S to elemental sulfur, the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV alleviates the inhibitory effects of H2S on methanotrophy. Strain SolV adapts to increasing H2S by expressing a sulfide-insensitive ba3-type terminal oxidase and grows as chemolithoautotroph using H2S as sole energy source. Genomic surveys revealed putative sulfide-oxidizing enzymes in numerous methanotrophs, suggesting that H2S oxidation is much more widespread in methanotrophs than previously assumed, enabling them to connect carbon and sulfur cycles in novel ways.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
- Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, 8092, Zurich, Switzerland
| | - Stijn H Peeters
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Sepehr S Mohammadi
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Tom Berben
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Timo van Erven
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Carmen A Iosif
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Theo van Alen
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands.
| | - Arjan Pol
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525AJ, Nijmegen, The Netherlands
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15
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Rafalska A, Walkiewicz A, Osborne B, Klumpp K, Bieganowski A. Variation in methane uptake by grassland soils in the context of climate change - A review of effects and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 871:162127. [PMID: 36764535 DOI: 10.1016/j.scitotenv.2023.162127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/19/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
Grassland soils are climate-dependent ecosystems that have a significant greenhouse gas mitigating function through their ability to store large amounts of carbon (C). However, what is often not recognized is that they can also exhibit a high methane (CH4) uptake capacity that could be influenced by future increases in atmospheric carbon dioxide (CO2) concentration and variations in temperature and water availability. While there is a wealth of information on C sequestration in grasslands there is less consensus on how climate change impacts on CH4 uptake or the underlying mechanisms involved. To address this, we assessed existing knowledge on the impact of climate change components on CH4 uptake by grassland soils. Increases in precipitation associated with soils with a high background soil moisture content generally resulted in a reduction in CH4 uptake or even net emissions, while the effect was opposite in soils with a relatively low background moisture content. Initially wet grasslands subject to the combined effects of warming and water deficits may absorb more CH4, mainly due to increased gas diffusivity. However, in the longer-term heat and drought stress may reduce the activity of methanotrophs when the mean soil moisture content is below the optimum for their survival. Enhanced plant productivity and growth under elevated CO2, increased soil moisture and changed nutrient concentrations, can differentially affect methanotrophic activity, which is often reduced by increasing N deposition. Our estimations showed that CH4 uptake in grassland soils can change from -57.7 % to +6.1 % by increased precipitation, from -37.3 % to +85.3 % by elevated temperatures, from +0.87 % to +92.4 % by decreased precipitation, and from -66.7 % to +27.3 % by elevated CO2. In conclusion, the analysis suggests that grasslands under the influence of warming and drought may absorb even more CH4, mainly because of reduced soil water contents and increased gas diffusivity.
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Affiliation(s)
- Adrianna Rafalska
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
| | - Anna Walkiewicz
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland.
| | - Bruce Osborne
- UCD School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, 4 Dublin, Ireland
| | - Katja Klumpp
- INRAE, University of Clermont Auvergne, VetAgro Sup, UREP Unité de Recherche sur l'Ecosystème Prairial, 63000 Clermont-Ferrand, France
| | - Andrzej Bieganowski
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland
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16
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Lee J, Yun J, Yang Y, Jung JY, Lee YK, Yuan J, Ding W, Freeman C, Kang H. Attenuation of Methane Oxidation by Nitrogen Availability in Arctic Tundra Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2647-2659. [PMID: 36719133 DOI: 10.1021/acs.est.2c05228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
CH4 emission in the Arctic has large uncertainty due to the lack of mechanistic understanding of the processes. CH4 oxidation in Arctic soil plays a critical role in the process, whereby removal of up to 90% of CH4 produced in soils by methanotrophs can occur before it reaches the atmosphere. Previous studies have reported on the importance of rising temperatures in CH4 oxidation, but because the Arctic is typically an N-limited system, fewer studies on the effects of inorganic nitrogen (N) have been reported. However, climate change and an increase of available N caused by anthropogenic activities have recently been reported, which may cause a drastic change in CH4 oxidation in Arctic soils. In this study, we demonstrate that excessive levels of available N in soil cause an increase in net CH4 emissions via the reduction of CH4 oxidation in surface soil in the Arctic tundra. In vitro experiments suggested that N in the form of NO3- is responsible for the decrease in CH4 oxidation via influencing soil bacterial and methanotrophic communities. The findings of our meta-analysis suggest that CH4 oxidation in the boreal biome is more susceptible to the addition of N than in other biomes. We provide evidence that CH4 emissions in Arctic tundra can be enhanced by an increase of available N, with profound implications for modeling CH4 dynamics in Arctic regions.
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Affiliation(s)
- Jaehyun Lee
- School of Civil and Environmental Engineering, Yonsei University, Seoul03722, South Korea
| | - Jeongeun Yun
- School of Civil and Environmental Engineering, Yonsei University, Seoul03722, South Korea
| | - Yerang Yang
- School of Civil and Environmental Engineering, Yonsei University, Seoul03722, South Korea
| | - Ji Young Jung
- Korea Polar Research Institute, Incheon21990, South Korea
| | - Yoo Kyung Lee
- Korea Polar Research Institute, Incheon21990, South Korea
| | - Junji Yuan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing210008, China
| | - Weixin Ding
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing210008, China
| | - Chris Freeman
- School of Natural Sciences, Bangor University, BangorLL57 2UW, U.K
| | - Hojeong Kang
- School of Civil and Environmental Engineering, Yonsei University, Seoul03722, South Korea
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17
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Yao X, Wang J, Hu B. How methanotrophs respond to pH: A review of ecophysiology. Front Microbiol 2023; 13:1034164. [PMID: 36687570 PMCID: PMC9853399 DOI: 10.3389/fmicb.2022.1034164] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/09/2022] [Indexed: 01/08/2023] Open
Abstract
Varying pH globally affects terrestrial microbial communities and biochemical cycles. Methanotrophs effectively mitigate methane fluxes in terrestrial habitats. Many methanotrophs grow optimally at neutral pH. However, recent discoveries show that methanotrophs grow in strongly acidic and alkaline environments. Here, we summarize the existing knowledge on the ecophysiology of methanotrophs under different pH conditions. The distribution pattern of diverse subgroups is described with respect to their relationship with pH. In addition, their responses to pH stress, consisting of structure-function traits and substrate affinity traits, are reviewed. Furthermore, we propose a putative energy trade-off model aiming at shedding light on the adaptation mechanisms of methanotrophs from a novel perspective. Finally, we take an outlook on methanotrophs' ecophysiology affected by pH, which would offer new insights into the methane cycle and global climate change.
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Affiliation(s)
- Xiangwu Yao
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China
| | - Jiaqi Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China
| | - Baolan Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China,Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, China,*Correspondence: Baolan Hu ✉
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18
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Howe KL, Seitz KW, Campbell LG, Baker BJ, Thrash JC, Rabalais NN, Rogener MK, Joye SB, Mason OU. Metagenomics and metatranscriptomics reveal broadly distributed, active, novel methanotrophs in the Gulf of Mexico hypoxic zone and in the marine water column. FEMS Microbiol Ecol 2022; 99:6909064. [PMID: 36520069 PMCID: PMC9874027 DOI: 10.1093/femsec/fiac153] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 11/17/2022] [Accepted: 12/20/2022] [Indexed: 12/23/2022] Open
Abstract
The northern Gulf of Mexico (nGOM) hypoxic zone is a shallow water environment where methane, a potent greenhouse gas, fluxes from sediments to bottom water and remains trapped due to summertime stratification. When the water column is destratified, an active planktonic methanotrophic community could mitigate the efflux of methane, which accumulates to high concentrations, to the atmosphere. To investigate the possibility of such a biofilter in the nGOM hypoxic zone we performed metagenome assembly, and metagenomic and metatranscriptomic read mapping. Methane monooxygenase (pmoA) was an abundant transcript, yet few canonical methanotrophs have been reported in this environment, suggesting a role for non-canonical methanotrophs. To determine the identity of these methanotrophs, we reconstructed six novel metagenome-assembled genomes (MAGs) in the Planctomycetota, Verrucomicrobiota and one putative Latescibacterota, each with at least one pmoA gene copy. Based on ribosomal protein phylogeny, closely related microbes (mostly from Tara Oceans) and isolate genomes were selected and co-analyzed with the nGOM MAGs. Gene annotation and read mapping suggested that there is a large, diverse and unrecognized community of active aerobic methanotrophs in the nGOM hypoxic zone and in the global ocean that could mitigate methane flux to the atmosphere.
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Affiliation(s)
- Kathryn L Howe
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, 32306, Tallahassee, United States
| | - Kiley W Seitz
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, 78373, Port Aransas, United States
| | - Lauren G Campbell
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, 32306, Tallahassee, United States
| | - Brett J Baker
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, 78373, Port Aransas, United States,Department of Integrative Biology, University of Texas at Austin, 78712, Austin, United States
| | - J Cameron Thrash
- Department of Biological Sciences, University of Southern California, 90089, Los Angeles, United States
| | - Nancy N Rabalais
- Department of Oceanography and Coastal Sciences, Louisiana State University, 70803, Baton Rouge, United States,Louisiana Universities Marine Consortium, 70344, Chauvin, United States
| | - Mary-Kate Rogener
- Department of Marine Sciences, University of Georgia, 30602, Athens, United States
| | - Samantha B Joye
- Department of Marine Sciences, University of Georgia, 30602, Athens, United States
| | - Olivia U Mason
- Corresponding author: Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, United States. E-mail:
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Neira G, Vergara E, Holmes DS. Genome-guided prediction of acid resistance mechanisms in acidophilic methanotrophs of phylogenetically deep-rooted Verrucomicrobia isolated from geothermal environments. Front Microbiol 2022; 13:900531. [PMID: 36212841 PMCID: PMC9543262 DOI: 10.3389/fmicb.2022.900531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Verrucomicrobia are a group of microorganisms that have been proposed to be deeply rooted in the Tree of Life. Some are methanotrophs that oxidize the potent greenhouse gas methane and are thus important in decreasing atmospheric concentrations of the gas, potentially ameliorating climate change. They are widespread in various environments including soil and fresh or marine waters. Recently, a clade of extremely acidophilic Verrucomicrobia, flourishing at pH < 3, were described from high-temperature geothermal ecosystems. This novel group could be of interest for studies about the emergence of life on Earth and to astrobiologists as homologs for possible extraterrestrial life. In this paper, we describe predicted mechanisms for survival of this clade at low pH and suggest its possible evolutionary trajectory from an inferred neutrophilic ancestor. Extreme acidophiles are defined as organisms that thrive in extremely low pH environments (≤ pH 3). Many are polyextremophiles facing high temperatures and high salt as well as low pH. They are important to study for both providing fundamental insights into biological mechanisms of survival and evolution in such extreme environments and for understanding their roles in biotechnological applications such as industrial mineral recovery (bioleaching) and mitigation of acid mine drainage. They are also, potentially, a rich source of novel genes and pathways for the genetic engineering of microbial strains. Acidophiles of the Verrucomicrobia phylum are unique as they are the only known aerobic methanotrophs that can grow optimally under acidic (pH 2–3) and moderately thermophilic conditions (50–60°C). Three moderately thermophilic genera, namely Methylacidiphilum, Methylacidimicrobium, and Ca. Methylacidithermus, have been described in geothermal environments. Most of the investigations of these organisms have focused on their methane oxidizing capabilities (methanotrophy) and use of lanthanides as a protein cofactor, with no extensive study that sheds light on the mechanisms that they use to flourish at extremely low pH. In this paper, we extend the phylogenetic description of this group of acidophiles using whole genome information and we identify several mechanisms, potentially involved in acid resistance, including “first line of defense” mechanisms that impede the entry of protons into the cell. These include the presence of membrane-associated hopanoids, multiple copies of the outer membrane protein (Slp), and inner membrane potassium channels (kup, kdp) that generate a reversed membrane potential repelling the intrusion of protons. Acidophilic Verrucomicrobia also display a wide array of proteins potentially involved in the “second line of defense” where protons that evaded the first line of defense and entered the cell are expelled or neutralized, such as the glutamate decarboxylation (gadAB) and phosphate-uptake systems. An exclusive N-type ATPase F0-F1 was identified only in acidophiles of Verrucomicrobia and is predicted to be a specific adaptation in these organisms. Phylogenetic analyses suggest that many predicted mechanisms are evolutionarily conserved and most likely entered the acidophilic lineage of Verrucomicrobia by vertical descent from a common ancestor. However, it is likely that some defense mechanisms such as gadA and kup entered the acidophilic Verrucomicrobia lineage by horizontal gene transfer.
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Affiliation(s)
- Gonzalo Neira
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
| | - Eva Vergara
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - David S. Holmes
- Center for Bioinformatics and Genome Biology, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- *Correspondence: David S. Holmes
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20
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Venturini AM, Dias NMS, Gontijo JB, Yoshiura CA, Paula FS, Meyer KM, Nakamura FM, da França AG, Borges CD, Barlow J, Berenguer E, Nüsslein K, Rodrigues JLM, Bohannan BJM, Tsai SM. Increased soil moisture intensifies the impacts of forest-to-pasture conversion on methane emissions and methane-cycling communities in the Eastern Amazon. ENVIRONMENTAL RESEARCH 2022; 212:113139. [PMID: 35337832 DOI: 10.1016/j.envres.2022.113139] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 02/24/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Climatic changes are altering precipitation patterns in the Amazon and may influence soil methane (CH4) fluxes due to the differential responses of methanogenic and methanotrophic microorganisms. However, it remains unclear if these climate feedbacks can amplify land-use-related impacts on the CH4 cycle. To better predict the responses of soil CH4-cycling microorganisms and emissions under altered moisture levels in the Eastern Brazilian Amazon, we performed a 30-day microcosm experiment manipulating the moisture content (original moisture; 60%, 80%, and 100% of field capacity - FC) of forest and pasture soils. Gas samples were collected periodically for gas chromatography analysis, and methanogenic archaeal and methanotrophic bacterial communities were assessed using quantitative PCR and metagenomics. Positive and negative daily CH4 fluxes were observed for forest and pasture, indicating that these soils can act as both CH4 sources and sinks. Cumulative emissions and the abundance of methanogenesis-related genes and taxonomic groups were affected by land use, moisture, and their interaction. Pasture soils at 100% FC had the highest abundance of methanogens and CH4 emissions, 22 times higher than forest soils under the same treatment. Higher ratios of methanogens to methanotrophs were found in pasture than in forest soils, even at field capacity conditions. Land use and moisture were significant factors influencing the composition of methanogenic and methanotrophic communities. The diversity and evenness of methanogens did not change throughout the experiment. In contrast, methanotrophs exhibited the highest diversity and evenness in pasture soils at 100% FC. Taken together, our results suggest that increased moisture exacerbates soil CH4 emissions and microbial responses driven by land-use change in the Amazon. This is the first report on the microbial CH4 cycle in Amazonian upland soils that combined one-month gas measurements with advanced molecular methods.
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Affiliation(s)
- Andressa M Venturini
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil; Princeton Institute for International and Regional Studies, Princeton University, Princeton, NJ, 08544, USA.
| | - Naissa M S Dias
- Environmental Biogeochemistry Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
| | - Júlia B Gontijo
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
| | - Caio A Yoshiura
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
| | - Fabiana S Paula
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil; Department of Biological Oceanography, Oceanographic Institute, University of São Paulo, São Paulo, SP, 05508-120, Brazil
| | - Kyle M Meyer
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403, USA; Department of Integrative Biology, University of California - Berkeley, Berkeley, CA, 94720, USA
| | - Fernanda M Nakamura
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
| | - Aline G da França
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
| | - Clovis D Borges
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
| | - Jos Barlow
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Erika Berenguer
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK; Environmental Change Institute, University of Oxford, Oxford, OX1 3QY, UK
| | - Klaus Nüsslein
- Department of Microbiology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jorge L M Rodrigues
- Department of Land, Air, and Water Resources, University of California - Davis, Davis, CA, 95616, USA
| | - Brendan J M Bohannan
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403, USA
| | - Siu M Tsai
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, 13416-000, Brazil
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21
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Schmitz RA, Mohammadi SS, van Erven T, Berben T, Jetten MSM, Pol A, Op den Camp HJM. Methanethiol Consumption and Hydrogen Sulfide Production by the Thermoacidophilic Methanotroph Methylacidiphilum fumariolicum SolV. Front Microbiol 2022; 13:857442. [PMID: 35422776 PMCID: PMC9003020 DOI: 10.3389/fmicb.2022.857442] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Methanotrophs aerobically oxidize methane to carbon dioxide to make a living and are known to degrade various other short chain carbon compounds as well. Volatile organic sulfur compounds such as methanethiol (CH3SH) are important intermediates in the sulfur cycle. Although volatile organic sulfur compounds co-occur with methane in various environments, little is known about how these compounds affect methanotrophy. The enzyme methanethiol oxidase catalyzing the oxidation of methanethiol has been known for decades, but only recently the mtoX gene encoding this enzyme was identified in a methylotrophic bacterium. The presence of a homologous gene in verrucomicrobial methanotrophs prompted us to examine how methanotrophs cope with methanethiol. Here, we show that the verrucomicrobial methanotroph Methylacidiphilum fumariolicum SolV consumes methanethiol and produces H2S, which is concurrently oxidized. Consumption of methanethiol is required since methanethiol inhibits methane oxidation. Cells incubated with ∼15 μM methanethiol from the start clearly showed inhibition of growth. After depletion of methanethiol, growth resumed within 1 day. Genes encoding a putative methanethiol oxidase were found in a variety of methanotrophs. Therefore, we hypothesize that methanethiol degradation is a widespread detoxification mechanism in methanotrophs in a range of environments.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands.,Environmental Chemistry, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zurich, Switzerland
| | - Sepehr S Mohammadi
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands
| | - Timo van Erven
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands
| | - Tom Berben
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands
| | - Arjan Pol
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Radboud Institute for Biological and Environmental Research, Radboud University, Nijmegen, Netherlands
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22
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Berenjkar P, Sparling R, Lozecznik S, Yuan Q. Methane oxidation in a landfill biowindow under wide seasonally fluctuating climatic conditions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:24623-24638. [PMID: 34825333 DOI: 10.1007/s11356-021-17566-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
In the current study, a pilot biowindow was constructed in a closed cell of a Canadian Landfill, undergoing high seasonal fluctuations in the temperature from -30 in winter to 35 in summer. The biowindow was filled with biosolids compost amended with yard waste and leaf compost with the ratio of 4:1 as the substrate layer. Two years of monitoring of methane (CH4) oxidation in the biowindow led to remarkable expected observations including a thick, solid winter frost cover affecting gas exchange in winter and temperatures above 45 ℃ in the biowindow in late summer. A high influx compared to the reported values was observed into the biowindow with an average value of 1137 g.m-2.d-1, consisting of 64% of CH4 and 36% of carbon dioxide (CO2) in the landfill gas. The variations in the temperature and moisture content (MC) of the compost layer in addition to the influx fluctuations affected CH4 oxidation efficiency; however, a high average CH4 oxidation rate of 237 g.m-2.d-1 was obtained, with CH4 being mostly oxidized at top layers. The laboratory batch experiments verified that thermophilic methane-oxidizing bacteria (MOB) were active throughout the study period and oxidized CH4 with a higher rate than mesophilic MOB. The methanotrophic potential of the compost mixture showed an average value of 282 µmol.g-1.d-1 in the entire period of the study which is in the range of the highest reported maximum CH4 oxidation rates. The adopted compost mixture was suitable for CH4 oxidation if the MC was above 30%. The significance of MC variations on CH4 oxidation rate depended on the temperature range within the biowindow. At temperatures below 2 ℃, between 29 and 31℃, and above 45 ℃, MC was not a controlling factor for mesophilic CH4 oxidation.
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Affiliation(s)
- Parvin Berenjkar
- Department of Civil Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada
| | - Richard Sparling
- Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | | | - Qiuyan Yuan
- Department of Civil Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada.
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23
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Variable Inhibition of Nitrous Oxide Reduction in Denitrifying Bacteria by Different Forms of Methanobactin. Appl Environ Microbiol 2022; 88:e0234621. [PMID: 35285718 DOI: 10.1128/aem.02346-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aerobic methanotrophic activity is highly dependent on copper availability, and methanotrophs have developed multiple strategies to collect copper. Specifically, when copper is limiting (ambient concentrations less than 1 μM), some methanotrophs produce and secret a small modified peptide (less than 1,300 Da) termed methanobactin (MB) that binds copper with high affinity. As MB is secreted into the environment, other microbes that require copper for their metabolism may be inhibited as MB may make copper unavailable; e.g., inhibition of denitrifiers as complete conversion nitrate to dinitrogen involves multiple enzymes, some of which are copper-dependent. Of key concern is inhibition of the copper-dependent nitrous oxide reductase (NosZ), the only known enzyme capable of converting nitrous oxide (N2O) to dinitrogen. Herein, we show that different forms of MB differentially affect copper uptake and N2O reduction by Pseudomonas stutzeri strain DCP-Ps1 (that expresses clade I NosZ) and Dechloromonas aromatica strain RCB (that expresses clade II NosZ). Specifically, in the presence of MB from Methylocystis sp. strain SB2 (SB2-MB), copper uptake and nosZ expression were more significantly reduced than in the presence of MB from Methylosinus trichosporium OB3b (OB3b-MB). Further, N2O accumulation increased more significantly for both P. stutzeri strain DCP-Ps1 and D. aromatica strain RCB in the presence of SB2-MB versus OB3b-MB. These data illustrate that copper competition between methanotrophs and denitrifying bacteria can be significant and that the extent of such competition is dependent on the form of MB that methanotrophs produce. IMPORTANCE Herein, it was demonstrated that the different forms of methanobactin differentially enhance N2O emissions from Pseudomonas stutzeri strain DCP-Ps1 (harboring clade I nitrous oxide reductase) and Dechloromonas aromatica strain RCB (harboring clade II nitrous oxide reductase). This work contributes to our understanding of how aerobic methanotrophs compete with denitrifiers for the copper uptake and also suggests how MBs prevent copper collection by denitrifiers, thus downregulating expression of nitrous oxide reductase. This study provides critical information for enhanced understanding of microbe-microbe interactions that are important for the development of better predictive models of net greenhouse gas emissions (i.e., methane and nitrous oxide) that are significantly controlled by microbial activity.
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24
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Kochetkova TV, Podosokorskaya OA, Elcheninov AG, Kublanov IV. Diversity of Thermophilic Prokaryotes Inhabiting Russian Natural Hot Springs. Microbiology (Reading) 2022. [DOI: 10.1134/s0026261722010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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25
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Genome Sequence of a Thermoacidophilic Methanotroph Belonging to the Verrucomicrobiota Phylum from Geothermal Hot Springs in Yellowstone National Park: A Metagenomic Assembly and Reconstruction. Microorganisms 2022; 10:microorganisms10010142. [PMID: 35056591 PMCID: PMC8779874 DOI: 10.3390/microorganisms10010142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/23/2021] [Accepted: 01/07/2022] [Indexed: 02/04/2023] Open
Abstract
Verrucomicrobiotal methanotrophs are thermoacidophilic methane oxidizers that have been isolated from volcanic and geothermal regions of the world. We used a metagenomic approach that entailed obtaining the whole genome sequence of a verrucomicrobiotal methanotroph from a microbial consortium enriched from samples obtained from Nymph Lake (89.9 °C, pH 2.73) in Yellowstone National Park in the USA. To identify and reconstruct the verrucomicrobiotal genome from Illumina NovaSeq 6000 sequencing data, we constructed a bioinformatic pipeline with various combinations of de novo assembly, alignment, and binning algorithms. Based on the marker gene (pmoA), we identified and assembled the Candidatus Methylacidiphilum sp. YNP IV genome (2.47 Mbp, 2392 ORF, and 41.26% GC content). In a comparison of average nucleotide identity between Ca. Methylacidiphilum sp. YNP IV and Ca. Methylacidiphilum fumariolicum SolV, its closest 16S rRNA gene sequence relative, is lower than 95%, suggesting that Ca. Methylacidiphilum sp. YNP IV can be regarded as a different species. The Ca. Methylacidiphilum sp. YNP IV genome assembly showed most of the key genes for methane metabolism, the CBB pathway for CO2 fixation, nitrogen fixation and assimilation, hydrogenases, and rare earth elements transporter, as well as defense mechanisms. The assembly and reconstruction of a thermoacidophilic methanotroph belonging to the Verrucomicrobiota phylum from a geothermal environment adds further evidence and knowledge concerning the diversity of biological methane oxidation and on the adaptation of this geochemically relevant reaction in extreme environments.
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26
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Wang B, Stirling E, He Z, Ma B, Zhang H, Zheng X, Xiao F, Yan Q. Pollution alters methanogenic and methanotrophic communities and increases dissolved methane in small ponds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 801:149723. [PMID: 34438138 DOI: 10.1016/j.scitotenv.2021.149723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 05/28/2023]
Abstract
Small ponds have become a hotspot of greenhouse gas emissions, but our understanding of methane (CH4) cycling and its biological regulation in small polluted ponds remains limited. To assess how pollution affects CH4 content, we investigated dissolved CH4 concentrations, water and sediments properties, methanogenic and methanotrophic communities in two types of small polluted ponds. Compared with low pollution (LP) ponds, high pollution (HP) ponds showed significantly (P < 0.05) higher dissolved CH4 in water. Sequencing of methyl coenzyme M reductase (mcrA) and particulate methane monooxygenase (pmoA) genes showed that HP led to significant (P < 0.05) shifts of CH4-cycling microbial communities, with increased Shannon index of sediment methanogenic communities and water methanotrophic communities. There were also strong negative associations (P < 0.05) between dissolved CH4 concentrations and interdomain methanogen-methanotroph network connectivity in water and sediments, respectively. The partial least squares path modeling indicated that dissolved oxygen, total organic carbon, ammonium nitrogen and nitrate nitrogen of water, and total nitrogen and total carbon of sediment, and CH4-cycling microbes could regulate the CH4 content. This study clarified the effects of environmental deterioration on CH4 cycling in small ponds, highlighting the use of methanogen-methanotroph network connectivity to assess the CH4 production.
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Affiliation(s)
- Binhao Wang
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 510006, China
| | - Erinne Stirling
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Acid Sulfate Soils Centre, School of Biological Sciences, The University of Adelaide, Adelaide 5005, Australia
| | - Zhili He
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 510006, China; College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Bin Ma
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310058, China; Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China
| | - Hangjun Zhang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Xiafei Zheng
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 510006, China
| | - Fanshu Xiao
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 510006, China
| | - Qingyun Yan
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 510006, China.
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Peat-Inhabiting Verrucomicrobia of the Order Methylacidiphilales Do Not Possess Methanotrophic Capabilities. Microorganisms 2021; 9:microorganisms9122566. [PMID: 34946166 PMCID: PMC8706344 DOI: 10.3390/microorganisms9122566] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 01/04/2023] Open
Abstract
Methanotrophic verrucomicrobia of the order Methylacidiphilales are known as extremely acidophilic, thermophilic or mesophilic bacteria that inhabit acidic geothermal ecosystems. The occurrence of verrucomicrobial methanotrophs in other types of acidic environments remains an open question. Notably, Methylacidiphilales-affiliated 16S rRNA gene sequences are commonly retrieved from acidic (pH 3.5–5.5) peatlands. In this study, we compared the patterns of verrucomicrobial diversity in four acidic raised bogs and six neutral fens located in European North Russia. Methylacidiphilales-like 16S rRNA gene reads displaying 83–86% similarity to 16S rRNA gene sequences of currently described verrucomicrobial methanotrophs were recovered exclusively from raised bogs. Laboratory incubation of peat samples with 10% methane for 3 weeks resulted in the pronounced increase of a relative abundance of alphaproteobacterial methanotrophs, while no response was detected for Methylacidiphilales-affiliated bacteria. Three metagenome-assembled genomes (MAGs) of peat-inhabiting Methylacidiphilales bacteria were reconstructed and examined for the presence of genes encoding methane monooxygenase enzymes and autotrophic carbon fixation pathways. None of these genomic determinants were detected in assembled MAGs. Metabolic reconstructions predicted a heterotrophic metabolism, with a potential to hydrolyze several plant-derived polysaccharides. As suggested by our analysis, peat-inhabiting representatives of the Methylacidiphilales are acidophilic aerobic heterotrophs, which comprise a sister family of the methanotrophic Methylacidiphilaceae.
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28
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Two TonB-dependent transporters in Methylosinus trichosporium OB3b are responsible for uptake of different forms of methanobactin and are involved in the canonical 'copper switch'. Appl Environ Microbiol 2021; 88:e0179321. [PMID: 34669437 DOI: 10.1128/aem.01793-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Copper is an important component of methanotrophic physiology as it controls the expression and activity of alternative forms of methane monooxygenase (MMO). To collect copper, some methanotrophs secrete a chalkophore or copper-binding compound called methanobactin (MB). MB is a ribosomally synthesized post-translationally modified polypeptide (RiPP) that, after binding copper, is collected by MbnT, a TonB-dependent transporter (TBDT). Structurally different forms of MB have been characterized, and here we show that different forms of MB are collected by specific TBDTs. Further, we report that in the model methanotroph, Methylosinus trichosporium OB3b, expression of the TBDT required for uptake of a different MB made by Methylocystis sp. strain SB2 (MB-SB2), is induced in the presence of MB-SB2, suggesting that methanotrophs have developed specific machinery and regulatory systems to actively take up MB from other methanotrophs for copper collection. Moreover, the canonical "copper-switch" in Ms. trichosporium OB3b that controls expression of alternative MMOs is apparent if one of the two TBDTs required for MB-OB3b and MB-SB2 uptake is knocked out, but is disrupted if both TBDTs are knocked out. These data indicate that MB uptake, including the uptake of exogenous MB, plays an important role in the copper switch in M. trichosporium OB3b and thus overall activity. Based on these data, we propose a revised model for the "copper-switch" in this methanotroph that involves MB uptake. IMPORTANCE In this study, we demonstrate that different TonB-dependent transporters (TBDTs) in the model methanotroph Methylosinus trichosporium OB3b are responsible for uptake of either endogenous MB or exogenous MB. Interestingly, the presence of exogenous MB induces expression of its specific TBDT in M. trichosporium OB3b, suggesting that this methanotroph is able to actively take up MB produced by others. This work contributes to our understanding of how microbes collect and compete for copper, and also helps inform how such uptake coordinates the expression of different forms of methane monooxygenase. Such studies are likely to be very important to develop a better understanding of methanotrophic interactions via synthesis and secretion of secondary metabolites such as methanobactin and thus provide additional means whereby these microbes can be manipulated for a variety of environmental and industrial purposes.
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29
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Awala SI, Gwak JH, Kim YM, Kim SJ, Strazzulli A, Dunfield PF, Yoon H, Kim GJ, Rhee SK. Verrucomicrobial methanotrophs grow on diverse C3 compounds and use a homolog of particulate methane monooxygenase to oxidize acetone. ISME JOURNAL 2021; 15:3636-3647. [PMID: 34158629 PMCID: PMC8630023 DOI: 10.1038/s41396-021-01037-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/26/2022]
Abstract
Short-chain alkanes (SCA; C2-C4) emitted from geological sources contribute to photochemical pollution and ozone production in the atmosphere. Microorganisms that oxidize SCA and thereby mitigate their release from geothermal environments have rarely been studied. In this study, propane-oxidizing cultures could not be grown from acidic geothermal samples by enrichment on propane alone, but instead required methane addition, indicating that propane was co-oxidized by methanotrophs. “Methylacidiphilum” isolates from these enrichments did not grow on propane as a sole energy source but unexpectedly did grow on C3 compounds such as 2-propanol, acetone, and acetol. A gene cluster encoding the pathway of 2-propanol oxidation to pyruvate via acetol was upregulated during growth on 2-propanol. Surprisingly, this cluster included one of three genomic operons (pmoCAB3) encoding particulate methane monooxygenase (PMO), and several physiological tests indicated that the encoded PMO3 enzyme mediates the oxidation of acetone to acetol. Acetone-grown resting cells oxidized acetone and butanone but not methane or propane, implicating a strict substrate specificity of PMO3 to ketones instead of alkanes. Another PMO-encoding operon, pmoCAB2, was induced only in methane-grown cells, and the encoded PMO2 could be responsible for co-metabolic oxidation of propane to 2-propanol. In nature, propane probably serves primarily as a supplemental growth substrate for these bacteria when growing on methane.
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Affiliation(s)
- Samuel Imisi Awala
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
| | - Joo-Han Gwak
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
| | - Yong-Man Kim
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
| | - So-Jeong Kim
- Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, 34132, Republic of Korea
| | - Andrea Strazzulli
- Department of Biology, University of Naples "Federico II", Complesso Universitario Di Monte S. Angelo, Via Cupa Nuova Cinthia 21, 80126, Naples, Italy
| | - Peter F Dunfield
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Hyeokjun Yoon
- Biological and Genetic Resources Assessment Division, National Institute of Biological Resources, 42 Hwangyeong-ro, Seo-gu, Incheon, 22689, Republic of Korea
| | - Geun-Joong Kim
- Department of Biological Sciences and Research Center of Ecomimetics, College of Natural Sciences, Chonnam National University, Yongbong-ro, Buk-gu, Gwangju, 61186, Republic of Korea
| | - Sung-Keun Rhee
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, 28644, Republic of Korea.
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Picone N, Blom P, Hogendoorn C, Frank J, van Alen T, Pol A, Gagliano AL, Jetten MSM, D'Alessandro W, Quatrini P, Op den Camp HJM. Metagenome Assembled Genome of a Novel Verrucomicrobial Methanotroph From Pantelleria Island. Front Microbiol 2021; 12:666929. [PMID: 34093485 PMCID: PMC8170126 DOI: 10.3389/fmicb.2021.666929] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/20/2021] [Indexed: 01/10/2023] Open
Abstract
Verrucomicrobial methanotrophs are a group of aerobic bacteria isolated from volcanic environments. They are acidophiles, characterized by the presence of a particulate methane monooxygenase (pMMO) and a XoxF-type methanol dehydrogenase (MDH). Metagenomic analysis of DNA extracted from the soil of Favara Grande, a geothermal area on Pantelleria Island, Italy, revealed the presence of two verrucomicrobial Metagenome Assembled Genomes (MAGs). One of these MAGs did not phylogenetically classify within any existing genus. After extensive analysis of the MAG, we propose the name of "Candidatus Methylacidithermus pantelleriae" PQ17 gen. nov. sp. nov. The MAG consisted of 2,466,655 bp, 71 contigs and 3,127 predicted coding sequences. Completeness was found at 98.6% and contamination at 1.3%. Genes encoding the pMMO and XoxF-MDH were identified. Inorganic carbon fixation might use the Calvin-Benson-Bassham cycle since all genes were identified. The serine and ribulose monophosphate pathways were incomplete. The detoxification of formaldehyde could follow the tetrahydrofolate pathway. Furthermore, "Ca. Methylacidithermus pantelleriae" might be capable of nitric oxide reduction but genes for dissimilatory nitrate reduction and nitrogen fixation were not identified. Unlike other verrucomicrobial methanotrophs, genes encoding for enzymes involved in hydrogen oxidation could not be found. In conclusion, the discovery of this new MAG expands the diversity and metabolism of verrucomicrobial methanotrophs.
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Affiliation(s)
- Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Pieter Blom
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Carmen Hogendoorn
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Jeroen Frank
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Theo van Alen
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Antonina L Gagliano
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Palermo, Italy
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
| | - Walter D'Alessandro
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo, Palermo, Italy
| | - Paola Quatrini
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research (IWWR), Radboud University, Nijmegen, Netherlands
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31
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Guerrero-Cruz S, Vaksmaa A, Horn MA, Niemann H, Pijuan M, Ho A. Methanotrophs: Discoveries, Environmental Relevance, and a Perspective on Current and Future Applications. Front Microbiol 2021; 12:678057. [PMID: 34054786 PMCID: PMC8163242 DOI: 10.3389/fmicb.2021.678057] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
Methane is the final product of the anaerobic decomposition of organic matter. The conversion of organic matter to methane (methanogenesis) as a mechanism for energy conservation is exclusively attributed to the archaeal domain. Methane is oxidized by methanotrophic microorganisms using oxygen or alternative terminal electron acceptors. Aerobic methanotrophic bacteria belong to the phyla Proteobacteria and Verrucomicrobia, while anaerobic methane oxidation is also mediated by more recently discovered anaerobic methanotrophs with representatives in both the bacteria and the archaea domains. The anaerobic oxidation of methane is coupled to the reduction of nitrate, nitrite, iron, manganese, sulfate, and organic electron acceptors (e.g., humic substances) as terminal electron acceptors. This review highlights the relevance of methanotrophy in natural and anthropogenically influenced ecosystems, emphasizing the environmental conditions, distribution, function, co-existence, interactions, and the availability of electron acceptors that likely play a key role in regulating their function. A systematic overview of key aspects of ecology, physiology, metabolism, and genomics is crucial to understand the contribution of methanotrophs in the mitigation of methane efflux to the atmosphere. We give significance to the processes under microaerophilic and anaerobic conditions for both aerobic and anaerobic methane oxidizers. In the context of anthropogenically influenced ecosystems, we emphasize the current and potential future applications of methanotrophs from two different angles, namely methane mitigation in wastewater treatment through the application of anaerobic methanotrophs, and the biotechnological applications of aerobic methanotrophs in resource recovery from methane waste streams. Finally, we identify knowledge gaps that may lead to opportunities to harness further the biotechnological benefits of methanotrophs in methane mitigation and for the production of valuable bioproducts enabling a bio-based and circular economy.
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Affiliation(s)
- Simon Guerrero-Cruz
- Catalan Institute for Water Research (ICRA), Girona, Spain
- Universitat de Girona, Girona, Spain
| | - Annika Vaksmaa
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, ’t Horntje, Netherlands
| | - Marcus A. Horn
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
| | - Helge Niemann
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, ’t Horntje, Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Maite Pijuan
- Catalan Institute for Water Research (ICRA), Girona, Spain
- Universitat de Girona, Girona, Spain
| | - Adrian Ho
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
- Division of Applied Life Sciences, Gyeongsang National University, Jinju, South Korea
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32
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Kumar M, Yadav AN, Saxena R, Rai PK, Paul D, Tomar RS. Novel methanotrophic and methanogenic bacterial communities from diverse ecosystems and their impact on environment. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2021. [DOI: 10.1016/j.bcab.2021.102005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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33
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Carere CR, Hards K, Wigley K, Carman L, Houghton KM, Cook GM, Stott MB. Growth on Formic Acid Is Dependent on Intracellular pH Homeostasis for the Thermoacidophilic Methanotroph Methylacidiphilum sp. RTK17.1. Front Microbiol 2021; 12:651744. [PMID: 33841379 PMCID: PMC8024496 DOI: 10.3389/fmicb.2021.651744] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Members of the genus Methylacidiphilum, a clade of metabolically flexible thermoacidophilic methanotrophs from the phylum Verrucomicrobia, can utilize a variety of substrates including methane, methanol, and hydrogen for growth. However, despite sequentially oxidizing methane to carbon dioxide via methanol and formate intermediates, growth on formate as the only source of reducing equivalents (i.e., NADH) has not yet been demonstrated. In many acidophiles, the inability to grow on organic acids has presumed that diffusion of the protonated form (e.g., formic acid) into the cell is accompanied by deprotonation prompting cytosolic acidification, which leads to the denaturation of vital proteins and the collapse of the proton motive force. In this work, we used a combination of biochemical, physiological, chemostat, and transcriptomic approaches to demonstrate that Methylacidiphilum sp. RTK17.1 can utilize formate as a substrate when cells are able to maintain pH homeostasis. Our findings show that Methylacidiphilum sp. RTK17.1 grows optimally with a circumneutral intracellular pH (pH 6.52 ± 0.04) across an extracellular range of pH 1.5–3.0. In batch experiments, formic acid addition resulted in no observable cell growth and cell death due to acidification of the cytosol. Nevertheless, stable growth on formic acid as the only source of energy was demonstrated in continuous chemostat cultures (D = 0.0052 h−1, td = 133 h). During growth on formic acid, biomass yields remained nearly identical to methanol-grown chemostat cultures when normalized per mole electron equivalent. Transcriptome analysis revealed the key genes associated with stress response: methane, methanol, and formate metabolism were differentially expressed in response to growth on formic acid. Collectively, these results show formic acid represents a utilizable source of energy/carbon to the acidophilic methanotrophs within geothermal environments. Findings expand the known metabolic flexibility of verrucomicrobial methanotrophs to include organic acids and provide insight into potential survival strategies used by these species during methane starvation.
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Affiliation(s)
- Carlo R Carere
- Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Center for Molecular Biodiscovery, Auckland, New Zealand
| | - Kathryn Wigley
- Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Luke Carman
- Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Karen M Houghton
- Geomicrobiology Research Group, Department of Geothermal Sciences, GNS Science, Taupō, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Center for Molecular Biodiscovery, Auckland, New Zealand
| | - Matthew B Stott
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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Abstract
Methanotrophic bacteria represent a potential route to methane utilization and mitigation of methane emissions. In the first step of their metabolic pathway, aerobic methanotrophs use methane monooxygenases (MMOs) to activate methane, oxidizing it to methanol. There are two types of MMOs: a particulate, membrane-bound enzyme (pMMO) and a soluble, cytoplasmic enzyme (sMMO). The two MMOs are completely unrelated, with different architectures, metal cofactors, and mechanisms. The more prevalent of the two, pMMO, is copper-dependent, but the identity of its copper active site remains unclear. By contrast, sMMO uses a diiron active site, the catalytic cycle of which is well understood. Here we review the current state of knowledge for both MMOs, with an emphasis on recent developments and emerging hypotheses. In addition, we discuss obstacles to developing expression systems, which are needed to address outstanding questions and to facilitate future protein engineering efforts.
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Affiliation(s)
- Christopher W Koo
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, IL 60208, USA.
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A Novel Moderately Thermophilic Facultative Methylotroph within the Class Alphaproteobacteria. Microorganisms 2021; 9:microorganisms9030477. [PMID: 33668875 PMCID: PMC7996495 DOI: 10.3390/microorganisms9030477] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/22/2021] [Indexed: 11/25/2022] Open
Abstract
Methylotrophic bacteria (non-methanotrophic methanol oxidizers) consuming reduced carbon compounds containing no carbon–carbon bonds as their sole carbon and energy source have been found in a great variety of environments. Here, we report a unique moderately thermophilic methanol-oxidising bacterium (strain LS7-MT) that grows optimally at 55 °C (with a growth range spanning 30 to 60 °C). The pure isolate was recovered from a methane-utilizing mixed culture enrichment from an alkaline thermal spring in the Ethiopia Rift Valley, and utilized methanol, methylamine, glucose and a variety of multi-carbon compounds. Phylogenetic analysis of the 16S rRNA gene sequences demonstrated that strain LS7-MT represented a new facultatively methylotrophic bacterium within the order Hyphomicrobiales of the class Alphaproteobacteria. This new strain showed 94 to 96% 16S rRNA gene identity to the two methylotroph genera, Methyloceanibacter and Methyloligella. Analysis of the draft genome of strain LS7-MT revealed genes for methanol dehydrogenase, essential for methanol oxidation. Functional and comparative genomics of this new isolate revealed genomic and physiological divergence from extant methylotrophs. Strain LS7-MT contained a complete mxaF gene cluster and xoxF1 encoding the lanthanide-dependent methanol dehydrogenase (XoxF). This is the first report of methanol oxidation at 55 °C by a moderately thermophilic bacterium within the class Alphaproteobacteria. These findings expand our knowledge of methylotrophy by the phylum Proteobacteria in thermal ecosystems and their contribution to global carbon and nitrogen cycles.
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36
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Picone N, Blom P, Wallenius AJ, Hogendoorn C, Mesman R, Cremers G, Gagliano AL, D'Alessandro W, Quatrini P, Jetten MSM, Pol A, Op den Camp HJM. Methylacidimicrobium thermophilum AP8, a Novel Methane- and Hydrogen-Oxidizing Bacterium Isolated From Volcanic Soil on Pantelleria Island, Italy. Front Microbiol 2021; 12:637762. [PMID: 33643272 PMCID: PMC7907005 DOI: 10.3389/fmicb.2021.637762] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/25/2021] [Indexed: 11/13/2022] Open
Abstract
The Favara Grande is a geothermal area located on Pantelleria Island, Italy. The area is characterized high temperatures in the top layer of the soil (60°C), low pH (3–5) and hydrothermal gas emissions mainly composed of carbon dioxide (CO2), methane (CH4), and hydrogen (H2). These geothermal features may provide a suitable niche for the growth of chemolithotrophic thermoacidophiles, including the lanthanide-dependent methanotrophs of the phylum Verrucomicrobia. In this study, we started enrichment cultures inoculated with soil of the Favara Grande at 50 and 60°C with CH4 as energy source and medium containing sufficient lanthanides at pH 3 and 5. From these cultures, a verrucomicrobial methanotroph could be isolated via serial dilution and floating filters techniques. The genome of strain AP8 was sequenced and based on phylogenetic analysis we propose to name this new species Methylacidimicrobium thermophilum AP8. The transcriptome data at μmax (0.051 ± 0.001 h−1, doubling time ~14 h) of the new strain showed a high expression of the pmoCAB2 operon encoding the membrane-bound methane monooxygenase and of the gene xoxF1, encoding the lanthanide-dependent methanol dehydrogenase. A second pmoCAB operon and xoxF2 gene were not expressed. The physiology of strain AP8 was further investigated and revealed an optimal growth in a pH range of 3–5 at 50°C, representing the first thermophilic strain of the genus Methylacidimicrobium. Moreover, strain AP8 had a KS(app) for methane of 8 ± 1 μM. Beside methane, a type 1b [NiFe] hydrogenase enabled hydrogen oxidation at oxygen concentrations up to 1%. Taken together, our results expand the knowledge on the characteristics and adaptations of verrucomicrobial methanotrophs in hydrothermal environments and add a new thermophilic strain to the genus Methylacidimicrobium.
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Affiliation(s)
- Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Pieter Blom
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Anna J Wallenius
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Carmen Hogendoorn
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Rob Mesman
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Geert Cremers
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | | | | | - Paola Quatrini
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Palermo, Italy
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
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Hogendoorn C, Picone N, van Hout F, Vijverberg S, Poghosyan L, van Alen TA, Frank J, Pol A, Gagliano AL, Jetten MSM, D'Alessandro W, Quatrini P, Op den Camp HJM. Draft genome of a novel methanotrophic Methylobacter sp. from the volcanic soils of Pantelleria Island. Antonie van Leeuwenhoek 2021; 114:313-324. [PMID: 33566237 PMCID: PMC7902576 DOI: 10.1007/s10482-021-01525-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/22/2021] [Indexed: 11/27/2022]
Abstract
The genus Methylobacter is considered an important and often dominant group of aerobic methane-oxidizing bacteria in many oxic ecosystems, where members of this genus contribute to the reduction of CH4 emissions. Metagenomic studies of the upper oxic layers of geothermal soils of the Favara Grande, Pantelleria, Italy, revealed the presence of various methane-oxidizing bacteria, and resulted in a near complete metagenome assembled genome (MAG) of an aerobic methanotroph, which was classified as a Methylobacter species. In this study, the Methylobacter sp. B2 MAG was used to investigate its metabolic potential and phylogenetic affiliation. The MAG has a size of 4,086,539 bp, consists of 134 contigs and 3955 genes were found, of which 3902 were protein coding genes. All genes for CH4 oxidation to CO2 were detected, including pmoCAB encoding particulate methane monooxygenase (pMMO) and xoxF encoding a methanol dehydrogenase. No gene encoding a formaldehyde dehydrogenase was present and the formaldehyde to formate conversion follows the tetrahydromethanopterin (H4MPT) pathway. “Ca. Methylobacter favarea” B2 uses the Ribulose-Mono-Phosphate (RuMP) pathway for carbon fixation. Analysis of the MAG indicates that Na+/H+ antiporters and the urease system might be important in the maintenance of pH homeostasis of this strain to cope with acidic conditions. So far, thermoacidophilic Methylobacter species have not been isolated, however this study indicates that members of the genus Methylobacter can be found in distinct ecosystems and their presence is not restricted to freshwater or marine sediments.
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Affiliation(s)
- Carmen Hogendoorn
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Femke van Hout
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Sophie Vijverberg
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Lianna Poghosyan
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Theo A van Alen
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Jeroen Frank
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Antonia L Gagliano
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palerma, Via U. La Malfa 153, 90146, Palermo, Italy
| | - Mike S M Jetten
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Walter D'Alessandro
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palerma, Via U. La Malfa 153, 90146, Palermo, Italy
| | - Paola Quatrini
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Ed. 16, 90128, Palermo, Italy
| | - Huub J M Op den Camp
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
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38
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Schmitz RA, Peeters SH, Versantvoort W, Picone N, Pol A, Jetten MSM, Op den Camp HJM. Verrucomicrobial methanotrophs: ecophysiology of metabolically versatile acidophiles. FEMS Microbiol Rev 2021; 45:6125968. [PMID: 33524112 PMCID: PMC8498564 DOI: 10.1093/femsre/fuab007] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Methanotrophs are an important group of microorganisms that counteract methane emissions to the atmosphere. Methane-oxidising bacteria of the Alpha- and Gammaproteobacteria have been studied for over a century, while methanotrophs of the phylum Verrucomicrobia are a more recent discovery. Verrucomicrobial methanotrophs are extremophiles that live in very acidic geothermal ecosystems. Currently, more than a dozen strains have been isolated, belonging to the genera Methylacidiphilum and Methylacidimicrobium. Initially, these methanotrophs were thought to be metabolically confined. However, genomic analyses and physiological and biochemical experiments over the past years revealed that verrucomicrobial methanotrophs, as well as proteobacterial methanotrophs, are much more metabolically versatile than previously assumed. Several inorganic gases and other molecules present in acidic geothermal ecosystems can be utilised, such as methane, hydrogen gas, carbon dioxide, ammonium, nitrogen gas and perhaps also hydrogen sulfide. Verrucomicrobial methanotrophs could therefore represent key players in multiple volcanic nutrient cycles and in the mitigation of greenhouse gas emissions from geothermal ecosystems. Here, we summarise the current knowledge on verrucomicrobial methanotrophs with respect to their metabolic versatility and discuss the factors that determine their diversity in their natural environment. In addition, key metabolic, morphological and ecological characteristics of verrucomicrobial and proteobacterial methanotrophs are reviewed.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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39
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Picone N, Mohammadi SS, Waajen AC, van Alen TA, Jetten MSM, Pol A, Op den Camp HJM. More Than a Methanotroph: A Broader Substrate Spectrum for Methylacidiphilum fumariolicum SolV. Front Microbiol 2020; 11:604485. [PMID: 33381099 PMCID: PMC7768010 DOI: 10.3389/fmicb.2020.604485] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/23/2020] [Indexed: 01/27/2023] Open
Abstract
Volcanic areas emit a number of gases including methane and other short chain alkanes, that may serve as energy source for the prevailing microorganisms. The verrucomicrobial methanotroph Methylacidiphilum fumariolicum SolV was isolated from a volcanic mud pot, and is able to grow under thermoacidophilic conditions on different gaseous substrates. Its genome contains three operons encoding a particulate methane monooxygenase (pMMO), the enzyme that converts methane to methanol. The expression of two of these pmo operons is subjected to oxygen-dependent regulation, whereas the expression of the third copy (pmoCAB3) has, so far, never been reported. In this study we investigated the ability of strain SolV to utilize short-chain alkanes and monitored the expression of the pmo operons under different conditions. In batch cultures and in carbon-limited continuous cultures, strain SolV was able to oxidize and grow on C1–C3 compounds. Oxidation of ethane did occur simultaneously with methane, while propane consumption only started once methane and ethane became limited. Butane oxidation was not observed. Transcriptome data showed that pmoCAB1 and pmoCAB3 were induced in the absence of methane and the expression of pmoCAB3 increased upon propane addition. Together the results of our study unprecedently show that a pMMO-containing methanotroph is able to co-metabolize other gaseous hydrocarbons, beside methane. Moreover, it expands the substrate spectrum of verrucomicrobial methanotrophs, supporting their high metabolic flexibility and adaptation to the harsh and dynamic conditions in volcanic ecosystems.
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Affiliation(s)
- Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Sepehr S Mohammadi
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Annemiek C Waajen
- School of Physics and Astronomy, Institute for Condensed Matter and Complex Systems, Edinburgh University, Edinburgh, United Kingdom
| | - Theo A van Alen
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
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Abstract
Volcanic and geothermal environments are characterized by low pH, high temperatures, and gas emissions consisting of mainly CO2 and varied CH4, H2S, and H2 contents which allow the formation of chemolithoautotrophic microbial communities. To determine the link between the emitted gases and the microbial community composition, geochemical and metagenomic analysis were performed. Soil samples of the geothermic region Favara Grande (Pantelleria, Italy) were taken at various depths (1 to 50 cm). Analysis of the gas composition revealed that CH4 and H2 have the potential to serve as the driving forces for the microbial community. Our metagenomic analysis revealed a high relative abundance of Bacteria in the top layer (1 to 10 cm), but the relative abundance of Archaea increased with depth from 32% to 70%. In particular, a putative hydrogenotrophic methanogenic archaeon, related to Methanocella conradii, appeared to have a high relative abundance (63%) in deeper layers. A variety of [NiFe]-hydrogenase genes were detected, showing that H2 was an important electron donor for microaerobic microorganisms in the upper layers. Furthermore, the bacterial population included verrucomicrobial and proteobacterial methanotrophs, the former showing an up to 7.8 times higher relative abundance. Analysis of the metabolic potential of this microbial community showed a clear capacity to oxidize CH4 aerobically, as several genes for distinct particulate methane monooxygenases and lanthanide-dependent methanol dehydrogenases (XoxF-type) were retrieved. Analysis of the CO2 fixation pathways showed the presence of the Calvin-Benson-Bassham cycle, the Wood-Ljungdahl pathway, and the (reverse) tricarboxylic acid (TCA) cycle, the latter being the most represented carbon fixation pathway. This study indicates that the methane emissions in the Favara Grande might be a combination of geothermal activity and biological processes and further provides insights into the diversity of the microbial population thriving on CH4 and H2 IMPORTANCE The Favara Grande nature reserve on the volcanic island of Pantelleria (Italy) is known for its geothermal gas emissions and high soil temperatures. These volcanic soil ecosystems represent "hot spots" of greenhouse gas emissions. The unique community might be shaped by the hostile conditions in the ecosystem, and it is involved in the cycling of elements such as carbon, hydrogen, sulfur, and nitrogen. Our metagenome study revealed that most of the microorganisms in this extreme environment are only distantly related to cultivated bacteria. The results obtained profoundly increased the understanding of these natural hot spots of greenhouse gas production/degradation and will help to enrich and isolate the microbial key players. After isolation, it will become possible to unravel the molecular mechanisms by which they adapt to extreme (thermo/acidophilic) conditions, and this may lead to new green enzymatic catalysts and technologies for industry.
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Semrau JD, DiSpirito AA, Obulisamy PK, Kang-Yun CS. Methanobactin from methanotrophs: genetics, structure, function and potential applications. FEMS Microbiol Lett 2020; 367:5804726. [PMID: 32166327 DOI: 10.1093/femsle/fnaa045] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022] Open
Abstract
Aerobic methane-oxidizing bacteria of the Alphaproteobacteria have been found to express a novel ribosomally synthesized post-translationally modified polypeptide (RiPP) termed methanobactin (MB). The primary function of MB in these microbes appears to be for copper uptake, but MB has been shown to have multiple capabilities, including oxidase, superoxide dismutase and hydrogen peroxide reductase activities, the ability to detoxify mercury species, as well as acting as an antimicrobial agent. Herein, we describe the diversity of known MBs as well as the genetics underlying MB biosynthesis. We further propose based on bioinformatics analyses that some methanotrophs may produce novel forms of MB that have yet to be characterized. We also discuss recent findings documenting that MBs play an important role in controlling copper availability to the broader microbial community, and as a result can strongly affect the activity of microbes that require copper for important enzymatic transformations, e.g. conversion of nitrous oxide to dinitrogen. Finally, we describe procedures for the detection/purification of MB, as well as potential medical and industrial applications of this intriguing RiPP.
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Affiliation(s)
- Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA 50011
| | | | - Christina S Kang-Yun
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
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Methanol Production by " Methylacidiphilum fumariolicum" SolV under Different Growth Conditions. Appl Environ Microbiol 2020; 86:AEM.01188-20. [PMID: 32631865 PMCID: PMC7480378 DOI: 10.1128/aem.01188-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022] Open
Abstract
The production of methanol, an important chemical, is completely dependent on natural gas. The current multistep chemical process uses high temperature and pressure to convert methane in natural gas to methanol. In this study, we used the methanotroph “Methylacidiphilum fumariolicum” SolV to achieve continuous methanol production from methane as the substrate. The production rate was highly dependent on the growth rate of this microorganism, and high conversion efficiencies were obtained. Using microorganisms for the production of methanol might enable the use of more sustainable sources of methane, such as biogas, rather than natural gas. Industrial methanol production converts methane from natural gas into methanol through a multistep chemical process. Biological methane-to-methanol conversion under moderate conditions and using biogas would be more environmentally friendly. Methanotrophs, bacteria that use methane as an energy source, convert methane into methanol in a single step catalyzed by the enzyme methane monooxygenase, but inhibition of methanol dehydrogenase, which catalyzes the subsequent conversion of methanol into formaldehyde, is a major challenge. In this study, we used the thermoacidophilic methanotroph “Methylacidiphilum fumariolicum” SolV for biological methanol production. This bacterium possesses a XoxF-type methanol dehydrogenase that is dependent on rare earth elements for activity. By using a cultivation medium nearly devoid of lanthanides, we reduced methanol dehydrogenase activity and obtained a continuous methanol-producing microbial culture. The methanol production rate and conversion efficiency were growth-rate dependent. A maximal conversion efficiency of 63% mol methanol produced per mol methane consumed was obtained at a relatively high growth rate, with a methanol production rate of 0.88 mmol/g (dry weight)/h. This study demonstrates that methanotrophs can be used for continuous methanol production. Full-scale application will require additional increases in the titer, production rate, and efficiency, which can be achieved by further decreasing the lanthanide concentration through the use of increased biomass concentrations and novel reactor designs to supply sufficient gases, including methane, oxygen, and hydrogen. IMPORTANCE The production of methanol, an important chemical, is completely dependent on natural gas. The current multistep chemical process uses high temperature and pressure to convert methane in natural gas to methanol. In this study, we used the methanotroph “Methylacidiphilum fumariolicum” SolV to achieve continuous methanol production from methane as the substrate. The production rate was highly dependent on the growth rate of this microorganism, and high conversion efficiencies were obtained. Using microorganisms for the production of methanol might enable the use of more sustainable sources of methane, such as biogas, rather than natural gas.
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Ren H, Huang B, Fernández-García V, Miesel J, Yan L, Lv C. Biochar and Rhizobacteria Amendments Improve Several Soil Properties and Bacterial Diversity. Microorganisms 2020; 8:microorganisms8040502. [PMID: 32244714 PMCID: PMC7232174 DOI: 10.3390/microorganisms8040502] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 11/16/2022] Open
Abstract
In the current context, there is a growing interest in reducing the use of chemical fertilizers and pesticides to promote ecological agriculture. The use of biochar and plant growth-promoting rhizobacteria (PGPR) is an environmentally friendly alternative that can improve soil conditions and increase ecosystem productivity. However, the effects of biochar and PGPR amendments on forest plantations are not well known. The aim of this study is to investigate the effects of biochar and PGPR applications on soil nutrients and bacterial community. To achieve this goal, we applied amendments of (i) biochar at 20 t hm−2, (ii) PGPR at 5 × 1010 CFU mL−1, and (iii) biochar at 20 t hm−2 + PGPR at 5 × 1010 CFU mL−1 in a eucalyptus seedling plantation in Guangxi, China. Three months after applying the amendments, we collected six soil samples from each treatment and from control plots. From each soil sample, we analyzed several physicochemical properties (pH, electrical conductivity, total N, inorganic N, NO3−-N, NH4+-N, total P, total K, and soil water content), and we determined the bacterial community composition by sequencing the ribosomal 16S rRNA. Results indicated that co-application of biochar and PGPR amendments significantly decreased concentrations of soil total P and NH4+-N, whereas they increased NO3-N, total K, and soil water content. Biochar and PGPR treatments increased the richness and diversity of soil bacteria and the relative abundance of specific bacterial taxa such as Actinobacteria, Gemmatimonadetes, and Cyanobacteria. In general, the microbial composition was similar in the two treatments with PGPR. We also found that soil physicochemical properties had no significant influence on the soil composition of bacterial phyla, but soil NH4+-N was significantly related to the soil community composition of dominant bacterial genus. Thus, our findings suggest that biochar and PGPR amendments could be useful to maintain soil sustainability in eucalyptus plantations.
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Affiliation(s)
- Han Ren
- Forestry College, Guangxi University, Daxue E Rd., Xiangtang District, Nanning 530004, Guangxi, China; (H.R.); (B.H.); (L.Y.)
| | - Baoling Huang
- Forestry College, Guangxi University, Daxue E Rd., Xiangtang District, Nanning 530004, Guangxi, China; (H.R.); (B.H.); (L.Y.)
| | - Víctor Fernández-García
- Area of Ecology, Department of Biodiversity and Environmental Management, Faculty of Biological and Environmental Sciences, University of León, 24071 Leon, Spain;
| | - Jessica Miesel
- Department of Plant, Soil and Microbial Sciences, Michigan State University, 1066 Bogue Street, East Lansing, MI 48824, USA;
| | - Li Yan
- Forestry College, Guangxi University, Daxue E Rd., Xiangtang District, Nanning 530004, Guangxi, China; (H.R.); (B.H.); (L.Y.)
| | - Chengqun Lv
- Forestry College, Guangxi University, Daxue E Rd., Xiangtang District, Nanning 530004, Guangxi, China; (H.R.); (B.H.); (L.Y.)
- Correspondence:
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A Novel Moderately Thermophilic Type Ib Methanotroph Isolated from an Alkaline Thermal Spring in the Ethiopian Rift Valley. Microorganisms 2020; 8:microorganisms8020250. [PMID: 32069978 PMCID: PMC7074724 DOI: 10.3390/microorganisms8020250] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/09/2020] [Accepted: 02/10/2020] [Indexed: 11/23/2022] Open
Abstract
Aerobic moderately thermophilic and thermophilic methane-oxidizing bacteria make a substantial contribution in the control of global warming through biological reduction of methane emissions and have a unique capability of utilizing methane as their sole carbon and energy source. Here, we report a novel moderately thermophilic Methylococcus-like Type Ib methanotroph recovered from an alkaline thermal spring (55.4 °C and pH 8.82) in the Ethiopian Rift Valley. The isolate, designated LS7-MC, most probably represents a novel species of a new genus in the family Methylococcaceae of the class Gammaproteobacteria. The 16S rRNA gene phylogeny indicated that strain LS7-MC is distantly related to the closest described relative, Methylococcus capsulatus (92.7% sequence identity). Growth was observed at temperatures of 30–60 °C (optimal, 51–55 °C), and the cells possessed Type I intracellular membrane (ICM). The comparison of the pmoA gene sequences showed that the strain was most closely related to M.capsulatus (87.8%). Soluble methane monooxygenase (sMMO) was not detected, signifying the biological oxidation process from methane to methanol by the particulate methane monooxygenase (pMMO). The other functional genes mxaF, cbbL and nifH were detected by PCR. To our knowledge, the new strain is the first isolated moderately thermophilic methanotroph from an alkaline thermal spring of the family Methylococcaceae. Furthermore, LS7-MC represents a previously unrecognized biological methane sink in thermal habitats, expanding our knowledge of its ecological role in methane cycling and aerobic methanotrophy.
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45
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Islam T, Larsen Ø, Birkeland NK. A Novel Cold-adapted Methylovulum species, with a High C16:1ω5c Content, Isolated from an Arctic Thermal Spring in Spitsbergen. Microbes Environ 2020; 35:ME20044. [PMID: 32536671 PMCID: PMC7511782 DOI: 10.1264/jsme2.me20044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 04/25/2020] [Indexed: 11/12/2022] Open
Abstract
A novel cold-adapted methane-oxidizing bacterium, termed TFB, was isolated from the thermoglacial Arctic karst spring, Trollosen, located in the South Spitsbergen National Park (Norway). The source water is cold and extremely low in phosphate and nitrate. The isolate belongs to the Methylovulum genus of gammaproteobacterial methanotrophs, with the closest phylogenetic affiliation with Methylovulum miyakonense and Methylovulum psychrotolerans (96.2 and 96.1% 16S rRNA gene sequence similarities, respectively). TFB is a strict aerobe that only grows in the presence of methane or methanol. It fixes atmospheric nitrogen and contains Type I intracellular membranes. The growth temperature range was 2-22°C, with an optimum at 13-18°C. The functional genes pmoA, mxaF, and nifH were identified by PCR, whereas mmoX and cbbL were not. C16:1ω5c was identified as the major fatty acid constituent, at an amount (>49%) not previously found in any methanotrophs, and is likely to play a major role in cold adaptation. Strain TFB may be regarded as a new psychrotolerant or psychrophilic species within the genus Methylovulum. The recovery of this cold-adapted bacterium from a neutral Arctic thermal spring increases our knowledge of the diversity and adaptation of extremophilic gammaproteobacterial methanotrophs in the candidate family "Methylomonadaceae".
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Affiliation(s)
- Tajul Islam
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Bergen Katedralskole, Kong Oscars gate 36, 5017 Bergen, Norway
| | - Øivind Larsen
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- NORCE Norwegian Research Centre AS, Bergen, Norway
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Mohammadi SS, Schmitz RA, Pol A, Berben T, Jetten MSM, Op den Camp HJM. The Acidophilic Methanotroph Methylacidimicrobium tartarophylax 4AC Grows as Autotroph on H 2 Under Microoxic Conditions. Front Microbiol 2019; 10:2352. [PMID: 31681216 PMCID: PMC6813726 DOI: 10.3389/fmicb.2019.02352] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/27/2019] [Indexed: 12/17/2022] Open
Abstract
Emissions of the strong greenhouse gas methane (CH4) to the atmosphere are mitigated by methanotrophic microorganisms. Methanotrophs found in extremely acidic geothermal systems belong to the phylum Verrucomicrobia. Thermophilic verrucomicrobial methanotrophs from the genus Methylacidiphilum can grow autotrophically on hydrogen gas (H2), but it is unknown whether this also holds for their mesophilic counterparts from the genus Methylacidimicrobium. To determine this, we examined H2 consumption and CO2 fixation by the mesophilic verrucomicrobial methanotroph Methylacidimicrobium tartarophylax 4AC. We found that strain 4AC grows autotrophically on H2 with a maximum growth rate of 0.0048 h–1 and a yield of 2.1 g dry weight⋅mol H2–1, which is about 12 and 41% compared to the growth rate and yield on methane, respectively. The genome of strain 4AC only encodes for an oxygen-sensitive group 1b [NiFe] hydrogenase and H2 is respired only when oxygen concentrations are below 40 μM. Phylogenetic analysis and genomic comparison of methanotrophs revealed diverse [NiFe] hydrogenases, presumably with varying oxygen sensitivity and affinity for H2, which could drive niche differentiation. Our results show that both thermophilic and mesophilic verrucomicrobial methanotrophs can grow as autotrophs on H2 as a sole energy source. Our results suggest that verrucomicrobial methanotrophs are particularly well-equipped to thrive in hostile volcanic ecosystems, since they can consume H2 as additional energy source.
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Affiliation(s)
- Sepehr S Mohammadi
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Tom Berben
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
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Imchen M, Kumavath R, Vaz ABM, Góes-Neto A, Barh D, Ghosh P, Kozyrovska N, Podolich O, Azevedo V. 16S rRNA Gene Amplicon Based Metagenomic Signatures of Rhizobiome Community in Rice Field During Various Growth Stages. Front Microbiol 2019; 10:2103. [PMID: 31616390 PMCID: PMC6764247 DOI: 10.3389/fmicb.2019.02103] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 08/26/2019] [Indexed: 11/21/2022] Open
Abstract
Rice is a major staple food across the globe. Its growth and productivity is highly dependent on the rhizobiome where crosstalk takes place between plant and the microbial community. Such interactions lead to selective enrichment of plant beneficial microbes which ultimately defines the crop health and productivity. In this study, rhizobiome modulation is documented throughout the development of rice plant. Based on 16S rRNA gene affiliation at genus level, abundance, and diversity of plant growth promoting bacteria increased during the growth stages. The observed α diversity and rhizobiome complexity increased significantly (p < 0.05) during plantation. PCoA indicates that different geographical locations shared similar rhizobiome diversity but exerted differential enrichment (p < 0.001). Diversity of enriched genera represented a sigmoid curve and subsequently declined after harvest. A major proportion of dominant enriched genera (p < 0.05, abundance > 0.1%), based on 16S rRNA gene, were plant growth promoting bacteria that produces siderophore, indole-3-acetic acid, aminocyclopropane-1-carboxylic acid, and antimicrobials. Hydrogenotrophic methanogens dominated throughout cultivation. Type I methanotrophs (n = 12) had higher diversity than type II methanotrophs (n = 6). However, the later had significantly higher abundance (p = 0.003). Strong enrichment pattern was also observed in type I methanotrophs being enriched during water logged stages. Ammonia oxidizing Archaea were several folds more abundant than ammonia oxidizing bacteria. K-strategists Nitrosospira and Nitrospira dominated ammonia and nitrite oxidizing bacteria, respectively. The study clarifies the modulation of rhizobiome according to the rice developmental stages, thereby opening up the possibilities of bio-fertilizer treatment based on each cultivation stages.
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Affiliation(s)
- Madangchanok Imchen
- Department of Genomic Sciences, School of Biological Sciences, Central University of Kerala, Kasaragod, India
| | - Ranjith Kumavath
- Department of Genomic Sciences, School of Biological Sciences, Central University of Kerala, Kasaragod, India
| | - Aline B M Vaz
- Molecular and Computational Biology of Fungi Laboratory, Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Aristóteles Góes-Neto
- Molecular and Computational Biology of Fungi Laboratory, Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Debmalya Barh
- Molecular and Computational Biology of Fungi Laboratory, Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.,Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), Purba Medinipur, India
| | - Preetam Ghosh
- Department of Computer Sciences, Virginia Commonwealth University, Richmond, VA, United States
| | - Natalia Kozyrovska
- Institute of Molecular Biology and Genetics, National Academy of Sciences, Kyiv, Ukraine
| | - Olga Podolich
- Institute of Molecular Biology and Genetics, National Academy of Sciences, Kyiv, Ukraine
| | - Vasco Azevedo
- Laboratório de Genética Celular e Molecular, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Kruse T, Ratnadevi CM, Erikstad HA, Birkeland NK. Complete genome sequence analysis of the thermoacidophilic verrucomicrobial methanotroph "Candidatus Methylacidiphilum kamchatkense" strain Kam1 and comparison with its closest relatives. BMC Genomics 2019; 20:642. [PMID: 31399023 PMCID: PMC6688271 DOI: 10.1186/s12864-019-5995-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/26/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The candidate genus "Methylacidiphilum" comprises thermoacidophilic aerobic methane oxidizers belonging to the Verrucomicrobia phylum. These are the first described non-proteobacterial aerobic methane oxidizers. The genes pmoCAB, encoding the particulate methane monooxygenase do not originate from horizontal gene transfer from proteobacteria. Instead, the "Ca. Methylacidiphilum" and the sister genus "Ca. Methylacidimicrobium" represent a novel and hitherto understudied evolutionary lineage of aerobic methane oxidizers. Obtaining and comparing the full genome sequences is an important step towards understanding the evolution and physiology of this novel group of organisms. RESULTS Here we present the closed genome of "Ca. Methylacidiphilum kamchatkense" strain Kam1 and a comparison with the genomes of its two closest relatives "Ca. Methylacidiphilum fumariolicum" strain SolV and "Ca. Methylacidiphilum infernorum" strain V4. The genome consists of a single 2,2 Mbp chromosome with 2119 predicted protein coding sequences. Genome analysis showed that the majority of the genes connected with metabolic traits described for one member of "Ca. Methylacidiphilum" is conserved between all three genomes. All three strains encode class I CRISPR-cas systems. The average nucleotide identity between "Ca. M. kamchatkense" strain Kam1 and strains SolV and V4 is ≤95% showing that they should be regarded as separate species. Whole genome comparison revealed a high degree of synteny between the genomes of strains Kam1 and SolV. In contrast, comparison of the genomes of strains Kam1 and V4 revealed a number of rearrangements. There are large differences in the numbers of transposable elements found in the genomes of the three strains with 12, 37 and 80 transposable elements in the genomes of strains Kam1, V4 and SolV respectively. Genomic rearrangements and the activity of transposable elements explain much of the genomic differences between strains. For example, a type 1h uptake hydrogenase is conserved between strains Kam1 and SolV but seems to have been lost from strain V4 due to genomic rearrangements. CONCLUSIONS Comparing three closed genomes of "Ca. Methylacidiphilum" spp. has given new insights into the evolution of these organisms and revealed large differences in numbers of transposable elements between strains, the activity of these explains much of the genomic differences between strains.
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Affiliation(s)
- Thomas Kruse
- Department of Biological Sciences, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway.
| | | | - Helge-André Erikstad
- Department of Biological Sciences, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway
| | - Nils-Kåre Birkeland
- Department of Biological Sciences, University of Bergen, P.O. Box 7803, 5020, Bergen, Norway.
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49
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Houghton KM, Carere CR, Stott MB, McDonald IR. Thermophilic methanotrophs: in hot pursuit. FEMS Microbiol Ecol 2019; 95:5543213. [DOI: 10.1093/femsec/fiz125] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 07/31/2019] [Indexed: 11/13/2022] Open
Abstract
ABSTRACTMethane is a potent greenhouse gas responsible for 20–30% of global climate change effects. The global methane budget is ∼500–600 Tg y−1, with the majority of methane produced via microbial processes, including anthropogenic-mediated sources such as ruminant animals, rice fields, sewage treatment facilities and landfills. It is estimated that microbially mediated methane oxidation (methanotrophy) consumes >50% of global methane flux each year. Methanotrophy research has primarily focused on mesophilic methanotrophic representatives and cooler environments such as freshwater, wetlands or marine habitats from which they are sourced. Nevertheless, geothermal emissions of geological methane, produced from magma and lithosphere degassing micro-seepages, mud volcanoes and other geological sources, contribute an estimated 33–75 Tg y−1 to the global methane budget. The aim of this review is to summarise current literature pertaining to the activity of thermophilic and thermotolerant methanotrophs, both proteobacterial (Methylocaldum, Methylococcus, Methylothermus) and verrucomicrobial (Methylacidiphilum). We assert, on the basis of recently reported molecular and geochemical data, that geothermal ecosystems host hitherto unidentified species capable of methane oxidation at higher temperatures.
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Affiliation(s)
- Karen M Houghton
- GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand
- School of Science, University of Waikato, Knighton Rd, Hamilton 3240, New Zealand
| | - Carlo R Carere
- GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand
- Department of Chemical and Process Engineering, University of Canterbury, 20 Kirkwood Ave, Upper Riccarton, Christchurch 8041, New Zealand
| | - Matthew B Stott
- GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand
- School of Biological Sciences, University of Canterbury, 20 Kirkwood Ave, Upper Riccarton, Christchurch 8041, New Zealand
| | - Ian R McDonald
- School of Science, University of Waikato, Knighton Rd, Hamilton 3240, New Zealand
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50
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Zakharenko AS, Galachyants YP, Morozov IV, Shubenkova OV, Morozov AA, Ivanov VG, Pimenov NV, Krasnopeev AY, Zemskaya TI. Bacterial Communities in Areas of Oil and Methane Seeps in Pelagic of Lake Baikal. MICROBIAL ECOLOGY 2019; 78:269-285. [PMID: 30483839 DOI: 10.1007/s00248-018-1299-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 11/20/2018] [Indexed: 06/09/2023]
Abstract
We have assessed the diversity of bacteria near oil-methane (area I) and methane (area II) seeps in the pelagic zone of Lake Baikal using massive parallel sequencing of 16S rRNA, pmoA, and mxaF gene fragments amplified from total DNA. At depths from the surface to 100 m, sequences belonging to Cyanobacteria dominated. In the communities to a depth of 200 m of the studied areas, Proteobacteria dominated the deeper layers of the water column. Alphaproteobacteria sequences were predominant in the community near the oil-methane seep, while the community near the methane seep was characterized by the prevalence of Alpha- and Gammaproteobacteria. Among representatives of these classes, type I methanotrophs prevailed in the 16S rRNA gene libraries from the near-bottom area, and type II methanotrophs were detected in minor quantities at different depths. In the analysis of the libraries of the pmoA and mxaF functional genes, we observed the different taxonomic composition of methanotrophic bacteria in the surface and deep layers of the water column. All pmoA sequences from area I were type II methanotrophs and were detected at a depth of 300 m, while sequences of type I methanotrophs were the most abundant in deep layers of the water column of area II. All mxaF gene sequences belonged to Methylobacterium representatives. Based on comparative analyses of 16S rRNA, pmoA, and mxaF gene fragment libraries, we suggest that there must be a wider spectrum of functional genes facilitating methane oxidation that were not detected with the primers used.
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Affiliation(s)
- Aleksandra S Zakharenko
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia.
| | - Yuriy P Galachyants
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia
| | - Igor V Morozov
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Olga V Shubenkova
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia
| | - Alexey A Morozov
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia
| | - Vyacheslav G Ivanov
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia
| | - Nikolay V Pimenov
- Research Center of Biotechnology, Russian Academy of Sciences, Winogradsky Institute of Microbiology, Moscow, Russia
| | - Andrey Y Krasnopeev
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia
| | - Tamara I Zemskaya
- Siberian Branch of the Russian Academy of Sciences, Limnological Institute, Ulan-Batorskaya Street 3, 664033, Irkutsk, Russia
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