1
|
Wang Y, Wang Y, Zhou K, Zhang H, Cheng M, Wang B, Yan X. Isolation of a facultative methanotroph Methylocystis iwaonis SD4 from rice rhizosphere and establishment of rapid genetic tools for it. Biotechnol Lett 2024; 46:713-724. [PMID: 38733438 DOI: 10.1007/s10529-024-03495-y] [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: 03/17/2024] [Revised: 04/10/2024] [Accepted: 04/21/2024] [Indexed: 05/13/2024]
Abstract
Methanotrophs of the genus Methylocystis are frequently found in rice paddies. Although more than ten facultative methanotrophs have been reported since 2005, none of these strains was isolated from paddy soil. Here, a facultative methane-oxidizing bacterium, Methylocystis iwaonis SD4, was isolated and characterized from rhizosphere samples of rice plants in Nanjing, China. This strain grew well on methane or methanol but was able to grow slowly using acetate or ethanol. Moreover, strain SD4 showed sustained growth at low concentrations of methane (100 and 500 ppmv). M. iwaonis SD4 could utilize diverse nitrogen sources, including nitrate, urea, ammonium as well as dinitrogen. Strain SD4 possessed genes encoding both the particulate methane monooxygenase and the soluble methane monooxygenase. Simple and rapid genetic manipulation methods were established for this strain, enabling vector transformation and unmarked genetic manipulation. Fast growth rate and efficient genetic tools make M. iwaonis SD4 an ideal model to study facultative methanotrophs, and the ability to grow on low concentration of methane implies its potential in methane removal.
Collapse
Affiliation(s)
- Yinghui Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Yuying Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Keyu Zhou
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Haili Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Minggen Cheng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Baozhan Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
- Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Key Lab of Organic-Based Fertilizers of China, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
| |
Collapse
|
2
|
Yu Y, Shi Y, Kwon YW, Choi Y, Kim Y, Na JG, Huh J, Lee J. A rationally designed miniature of soluble methane monooxygenase enables rapid and high-yield methanol production in Escherichia coli. Nat Commun 2024; 15:4399. [PMID: 38782897 PMCID: PMC11116448 DOI: 10.1038/s41467-024-48671-w] [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: 10/02/2023] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
Soluble methane monooxygenase (sMMO) oxidizes a wide range of carbon feedstocks (C1 to C8) directly using intracellular NADH and is a useful means in developing green routes for industrial manufacturing of chemicals. However, the high-throughput biosynthesis of active recombinant sMMO and the ensuing catalytic oxidation have so far been unsuccessful due to the structural and functional complexity of sMMO, comprised of three functionally complementary components, which remains a major challenge for its industrial applications. Here we develop a catalytically active miniature of sMMO (mini-sMMO), with a turnover frequency of 0.32 s-1, through an optimal reassembly of minimal and modified components of sMMO on catalytically inert and stable apoferritin scaffold. We characterise the molecular characteristics in detail through in silico and experimental analyses and verifications. Notably, in-situ methanol production in a high-cell-density culture of mini-sMMO-expressing recombinant Escherichia coli resulted in higher yield and productivity (~ 3.0 g/L and 0.11 g/L/h, respectively) compared to traditional methanotrophic production.
Collapse
Affiliation(s)
- Yeonhwa Yu
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Yongfan Shi
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Young Wan Kwon
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Yoobin Choi
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Yusik Kim
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - June Huh
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea.
| | - Jeewon Lee
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea.
| |
Collapse
|
3
|
Awala SI, Gwak JH, Kim Y, Jung MY, Dunfield PF, Wagner M, Rhee SK. Nitrous oxide respiration in acidophilic methanotrophs. Nat Commun 2024; 15:4226. [PMID: 38762502 PMCID: PMC11102522 DOI: 10.1038/s41467-024-48161-z] [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: 01/03/2024] [Accepted: 04/22/2024] [Indexed: 05/20/2024] Open
Abstract
Aerobic methanotrophic bacteria are considered strict aerobes but are often highly abundant in hypoxic and even anoxic environments. Despite possessing denitrification genes, it remains to be verified whether denitrification contributes to their growth. Here, we show that acidophilic methanotrophs can respire nitrous oxide (N2O) and grow anaerobically on diverse non-methane substrates, including methanol, C-C substrates, and hydrogen. We study two strains that possess N2O reductase genes: Methylocella tundrae T4 and Methylacidiphilum caldifontis IT6. We show that N2O respiration supports growth of Methylacidiphilum caldifontis at an extremely acidic pH of 2.0, exceeding the known physiological pH limits for microbial N2O consumption. Methylocella tundrae simultaneously consumes N2O and CH4 in suboxic conditions, indicating robustness of its N2O reductase activity in the presence of O2. Furthermore, in O2-limiting conditions, the amount of CH4 oxidized per O2 reduced increases when N2O is added, indicating that Methylocella tundrae can direct more O2 towards methane monooxygenase. Thus, our results demonstrate that some methanotrophs can respire N2O independently or simultaneously with O2, which may facilitate their growth and survival in dynamic environments. Such metabolic capability enables these bacteria to simultaneously reduce the release of the key greenhouse gases CO2, CH4, and N2O.
Collapse
Affiliation(s)
- Samuel Imisi Awala
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, 28644, Republic of Korea
- Center for Ecology and Environmental Toxicology, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, 28644, South 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
| | - Man-Young Jung
- Interdisciplinary Graduate Programme in Advance Convergence Technology and Science, Jeju National University, Jeju, Republic of Korea
- Department of Science Education, Jeju National University, Jeju, Republic of Korea
- Jeju Microbiome Center, Jeju National University, Jeju, Republic of Korea
| | - Peter F Dunfield
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Michael Wagner
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
- Department of Chemistry and Bioscience, Center for Microbial Communities, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg, Denmark
| | - Sung-Keun Rhee
- Department of Biological Sciences and Biotechnology, Chungbuk National University, 1 Chungdae-ro, Seowon-Gu, Cheongju, 28644, Republic of Korea.
| |
Collapse
|
4
|
Hidalgo-Martinez K, Giachini AJ, Schneider M, Soriano A, Baessa MP, Martins LF, de Oliveira VM. Shifts in structure and dynamics of the soil microbiome in biofuel/fuel blend-affected areas triggered by different bioremediation treatments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:33663-33684. [PMID: 38687451 DOI: 10.1007/s11356-024-33304-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 04/09/2024] [Indexed: 05/02/2024]
Abstract
The use of biofuels has grown in the last decades as a consequence of the direct environmental impacts of fossil fuel use. Elucidating structure, diversity, species interactions, and assembly mechanisms of microbiomes is crucial for understanding the influence of environmental disturbances. However, little is known about how contamination with biofuel/petrofuel blends alters the soil microbiome. Here, we studied the dynamics in the soil microbiome structure and composition of four field areas under long-term contamination with biofuel/fossil fuel blends (ethanol 10% and gasoline 90%-E10; ethanol 25% and gasoline 75%-E25; soybean biodiesel 20% and diesel 80%-B20) submitted to different bioremediation treatments along a temporal gradient. Soil microbiomes from biodiesel-polluted areas exhibited higher richness and diversity index values and more complex microbial communities than ethanol-polluted areas. Additionally, monitored natural attenuation B20-polluted areas were less affected by perturbations caused by bioremediation treatments. As a consequence, once biostimulation was applied, the degradation was slower compared with areas previously actively treated. In soils with low diversity and richness, the impact of bioremediation treatments on the microbiomes was greater, and as a result, the hydrocarbon degradation extent was higher. The network analysis showed that all abundant keystone taxa corresponded to well-known degraders, suggesting that the abundant species are core targets for biostimulation in soil remediation processes. Altogether, these findings showed that the knowledge gained through the study of microbiomes in contaminated areas may help design and conduct optimized bioremediation approaches, paving the way for future rationalized and efficient pollutant mitigation strategies.
Collapse
Affiliation(s)
- Kelly Hidalgo-Martinez
- Divisão de Recursos Microbianos, Centro Pluridisciplinar de Pesquisas Químicas, Biológicas E Agrícolas (CPQBA), Universidade Estadual de Campinas (UNICAMP), Paulínia, SP, CEP 13148-218, Brazil.
- Programa de Pós-Graduação de Genética E Biologia Molecular, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, CEP 13083-970, Brazil.
| | - Admir José Giachini
- Núcleo Ressacada de Pesquisas Em Meio Ambiente (REMA)-Department of Microbiology, Federal University of Santa Catarina (UFSC), Campus Universitário Sul da Ilha-Rua José Olímpio da Silva, 1326-Bairro Tapera, Florianópolis, SC, 88049-500, Brazil
| | - Marcio Schneider
- Núcleo Ressacada de Pesquisas Em Meio Ambiente (REMA)-Department of Microbiology, Federal University of Santa Catarina (UFSC), Campus Universitário Sul da Ilha-Rua José Olímpio da Silva, 1326-Bairro Tapera, Florianópolis, SC, 88049-500, Brazil
| | - Adriana Soriano
- PETROBRAS/R&D Center (CENPES), Cidade Universitária, Av. Horácio Macedo, Ilha Do Fundão, Rio de Janeiro, 950, ZIP 21941-915, Brazil
| | - Marcus Paulus Baessa
- PETROBRAS/R&D Center (CENPES), Cidade Universitária, Av. Horácio Macedo, Ilha Do Fundão, Rio de Janeiro, 950, ZIP 21941-915, Brazil
| | - Luiz Fernando Martins
- PETROBRAS/R&D Center (CENPES), Cidade Universitária, Av. Horácio Macedo, Ilha Do Fundão, Rio de Janeiro, 950, ZIP 21941-915, Brazil
| | - Valéria Maia de Oliveira
- Divisão de Recursos Microbianos, Centro Pluridisciplinar de Pesquisas Químicas, Biológicas E Agrícolas (CPQBA), Universidade Estadual de Campinas (UNICAMP), Paulínia, SP, CEP 13148-218, Brazil
| |
Collapse
|
5
|
Yakubu B, Appiah EM, Adu AF. Pangenome Analysis of Helicobacter pylori Isolates from Selected Areas of Africa Indicated Diverse Antibiotic Resistance and Virulence Genes. Int J Genomics 2024; 2024:5536117. [PMID: 38469580 PMCID: PMC10927345 DOI: 10.1155/2024/5536117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/20/2023] [Accepted: 02/06/2024] [Indexed: 03/13/2024] Open
Abstract
The challenge facing Helicobacter pylori (H. pylori) infection management in some parts of Africa is the evolution of drug-resistant species, the lack of gold standard in diagnostic methods, and the ineffectiveness of current vaccines against the bacteria. It is being established that even though clinical consequences linked to the bacteria vary geographically, there is rather a generic approach to treatment. This situation has remained problematic in the successful fight against the bacteria in parts of Africa. As a result, this study compared the genomes of selected H. pylori isolates from selected areas of Africa and evaluated their virulence and antibiotic drug resistance, those that are highly pathogenic and are associated with specific clinical outcomes and those that are less virulent and rarely associated with clinical outcomes. 146 genomes of H. pylori isolated from selected locations of Africa were sampled, and bioinformatic tools such as Abricate, CARD RGI, MLST, Prokka, Roary, Phandango, Google Sheets, and iTOLS were used to compare the isolates and their antibiotic resistance or susceptibility. Over 20 k virulence and AMR genes were observed. About 95% of the isolates were genetically diverse, 90% of the isolates harbored shell genes, and 50% harbored cloud and core genes. Some isolates did not retain the cagA and vacA genes. Clarithromycin, metronidazole, amoxicillin, and tinidazole were resistant to most AMR genes (vacA, cagA, oip, and bab). Conclusion. This study found both virulence and AMR genes in all H. pylori strains in all the selected geographies around Africa with differing quantities. MLST, Pangenome, and ORF analyses showed disparities among the isolates. This in general could imply diversities in terms of genetics, evolution, and protein production. Therefore, generic administration of antibiotics such as clarithromycin, amoxicillin, and erythromycin as treatment methods in the African subregion could be contributing to the spread of the bacterium's antibiotic resistance.
Collapse
Affiliation(s)
- Biigba Yakubu
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Edwin Moses Appiah
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Andrews Frimpong Adu
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| |
Collapse
|
6
|
Wutkowska M, Tláskal V, Bordel S, Stein LY, Nweze JA, Daebeler A. Leveraging genome-scale metabolic models to understand aerobic methanotrophs. THE ISME JOURNAL 2024; 18:wrae102. [PMID: 38861460 PMCID: PMC11195481 DOI: 10.1093/ismejo/wrae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/20/2024] [Accepted: 06/10/2024] [Indexed: 06/13/2024]
Abstract
Genome-scale metabolic models (GEMs) are valuable tools serving systems biology and metabolic engineering. However, GEMs are still an underestimated tool in informing microbial ecology. Since their first application for aerobic gammaproteobacterial methane oxidizers less than a decade ago, GEMs have substantially increased our understanding of the metabolism of methanotrophs, a microbial guild of high relevance for the natural and biotechnological mitigation of methane efflux to the atmosphere. Particularly, GEMs helped to elucidate critical metabolic and regulatory pathways of several methanotrophic strains, predicted microbial responses to environmental perturbations, and were used to model metabolic interactions in cocultures. Here, we conducted a systematic review of GEMs exploring aerobic methanotrophy, summarizing recent advances, pointing out weaknesses, and drawing out probable future uses of GEMs to improve our understanding of the ecology of methane oxidizers. We also focus on their potential to unravel causes and consequences when studying interactions of methane-oxidizing bacteria with other methanotrophs or members of microbial communities in general. This review aims to bridge the gap between applied sciences and microbial ecology research on methane oxidizers as model organisms and to provide an outlook for future studies.
Collapse
Affiliation(s)
- Magdalena Wutkowska
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
| | - Vojtěch Tláskal
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
| | - Sergio Bordel
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Valladolid 47011, Spain
- Institute of Sustainable Processes, Valladolid 47011, Spain
| | - Lisa Y Stein
- Department of Biological Sciences, Faculty of Science, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Justus Amuche Nweze
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
- Department of Science Laboratory Technology, Faculty of Physical Sciences, University of Nigeria, Nsukka 410001, Nigeria
| | - Anne Daebeler
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
| |
Collapse
|
7
|
Zhao M, Huang M, Li Z. Exploring the therapeutic potential of recombinant human lysozyme: a review on wound management system with antibacterial. Front Bioeng Biotechnol 2023; 11:1292149. [PMID: 38026866 PMCID: PMC10646323 DOI: 10.3389/fbioe.2023.1292149] [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: 09/11/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Lysozyme, a natural antibacterial enzyme protein, possesses the ability to dissolve the cell walls of Gram-positive bacteria, demonstrating broad-spectrum antibacterial activity. Despite its significant potential in treating wound infections and promoting wound healing, its widespread clinical application has yet to be realized. Current research is primarily focused on carrier-based delivery systems for lysozyme. In this review, we discuss four delivery systems that can be employed for lysozyme in wound healing treatment, specifically hydrogels, nanofilms, electrospun fibrous membranes, and modified-lysozyme composite systems. These systems not only enhance the stability of lysozyme but also enable its controlled and sustained release at wound sites, potentially overcoming some of the challenges associated with its direct application. Lastly, we delve into the perspectives and challenges related to the use of these delivery systems, hoping to spur further research and innovation in this promising field.
Collapse
Affiliation(s)
- Meiping Zhao
- Nursing Department, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Meili Huang
- Nursing Department, Sir Run Run Shaw Hospital Affiliated to Zhejiang University School of Medicine Alar Hospital, Alar, China
| | - Zhen Li
- Emergency Department, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
8
|
Venetz J, Żygadłowska OM, Lenstra WK, van Helmond NAGM, Nuijten GHL, Wallenius AJ, Dalcin Martins P, Slomp CP, Jetten MSM, Veraart AJ. Versatile methanotrophs form an active methane biofilter in the oxycline of a seasonally stratified coastal basin. Environ Microbiol 2023; 25:2277-2288. [PMID: 37381163 DOI: 10.1111/1462-2920.16448] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 05/31/2023] [Indexed: 06/30/2023]
Abstract
The potential and drivers of microbial methane removal in the water column of seasonally stratified coastal ecosystems and the importance of the methanotrophic community composition for ecosystem functioning are not well explored. Here, we combined depth profiles of oxygen and methane with 16S rRNA gene amplicon sequencing, metagenomics and methane oxidation rates at discrete depths in a stratified coastal marine system (Lake Grevelingen, The Netherlands). Three amplicon sequence variants (ASVs) belonging to different genera of aerobic Methylomonadaceae and the corresponding three methanotrophic metagenome-assembled genomes (MOB-MAGs) were retrieved by 16S rRNA sequencing and metagenomic analysis, respectively. The abundances of the different methanotrophic ASVs and MOB-MAGs peaked at different depths along the methane oxygen counter-gradient and the MOB-MAGs show a quite diverse genomic potential regarding oxygen metabolism, partial denitrification and sulphur metabolism. Moreover, potential aerobic methane oxidation rates indicated high methanotrophic activity throughout the methane oxygen counter-gradient, even at depths with low in situ methane or oxygen concentration. This suggests that niche-partitioning with high genomic versatility of the present Methylomonadaceae might contribute to the functional resilience of the methanotrophic community and ultimately the efficiency of methane removal in the stratified water column of a marine basin.
Collapse
Affiliation(s)
- Jessica Venetz
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Olga M Żygadłowska
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Wytze K Lenstra
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Niels A G M van Helmond
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Guylaine H L Nuijten
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Anna J Wallenius
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Paula Dalcin Martins
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Caroline P Slomp
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Annelies J Veraart
- Department of Aquatic Ecology and Environmental Biology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| |
Collapse
|
9
|
Xue R, Zhang K, Liu X, Jiang B, Luo H, Li M, Mo Y, Liu C, Li L, Fan L, Chen W, Cheng L, Chen J, Chen F, Zhuang D, Qing J, Lin Y, Zhang X. Variations of methane fluxes and methane microbial community composition with soil depth in the riparian buffer zone of a sponge city park. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 339:117823. [PMID: 37129967 DOI: 10.1016/j.jenvman.2023.117823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/10/2023] [Accepted: 03/26/2023] [Indexed: 05/03/2023]
Abstract
Riparian buffers benefit both natural and man-made ecosystems by preventing soil erosion, retaining soil nutrients, and filtering pollutants. Nevertheless, the relationship between vertical methane fluxes, soil carbon, and methane microbial communities in riparian buffers remains unclear. This study examined vertical methane fluxes, soil carbon, and methane microbial communities in three different soil depths (0-5 cm, 5-10 cm, and 10-15 cm) within a riparian buffer of a Sponge City Park for one year. Structural equation model (SEM) results demonstrated that vertical methane fluxes varied with soil depths (λ = -0.37) and were primarily regulated by methanogenic community structure (λ = 0.78). Notably, mathematical regression results proposed that mcrA/pmoA ratio (R2 = 0.8) and methanogenic alpha diversity/methanotrophic alpha diversity ratio (R2 = 0.8) could serve as valid predictors of vertical variation in methane fluxes in the riparian buffer of urban river. These findings suggest that vertical variation of methane fluxes in riparian buffer soils is mainly influenced by carbon inputs and methane microbial abundance and community diversity. The study's results quantitatively the relationship between methane fluxes in riparian buffer soils and abiotic and biotic factors in the vertical direction, therefore contributing to the further development of mathematical models of soil methane emissions.
Collapse
Affiliation(s)
- Ru Xue
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China; Limnology, Department of Ecology and Genetics, Uppsala University, Uppsala, 75236, Sweden
| | - Ke Zhang
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China; Sichuan Higher Education Engineering Research Center for Disaster Prevention and Mitigation of Village Construction, Sichuan Agricultural University, Chengdu, 611830, China
| | - Xiaoling Liu
- Department of Information Engineering, Sichuan Water Conservancy Vocational College, Chengdu, 611231, China
| | - Bing Jiang
- Dujiangyan Campus, Sichuan Agricultural University, Chengdu, 611830, China
| | - Hongbing Luo
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China; Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China; Sichuan Higher Education Engineering Research Center for Disaster Prevention and Mitigation of Village Construction, Sichuan Agricultural University, Chengdu, 611830, China.
| | - Mei Li
- School of Urban and Rural Construction, Chengdu University, Chengdu, 610106, China
| | - You Mo
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China; Sichuan Higher Education Engineering Research Center for Disaster Prevention and Mitigation of Village Construction, Sichuan Agricultural University, Chengdu, 611830, China
| | - Cheng Liu
- Dujiangyan Campus, Sichuan Agricultural University, Chengdu, 611830, China
| | - Lin Li
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Liangqian Fan
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Wei Chen
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Lin Cheng
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Jia Chen
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Fenghui Chen
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Daiwei Zhuang
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Jing Qing
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Yuanmao Lin
- Department of Municipal Engineering, College of Civil Engineering, Sichuan Agricultural University, Chengdu, 611830, China
| | - Xiaohong Zhang
- College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China
| |
Collapse
|
10
|
Areniello M, Matassa S, Esposito G, Lens PNL. Microbial protein production from sulfide-rich biogas through an enrichment of methane- and sulfur-oxidizing bacteria. BIORESOURCE TECHNOLOGY 2023:129237. [PMID: 37244308 DOI: 10.1016/j.biortech.2023.129237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/21/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023]
Abstract
This study evaluated the possibility of combining methane oxidizing bacteria (MOB) with sulfur oxidizing bacteria (SOB) to enable the utilization of sulfide-rich biogas for microbial protein production. For this purpose, a MOB-SOB mixed-culture enriched by feeding both methane and sulfide was benchmarked against an enrichment of solely MOB. Different CH4:O2 ratios, starting pH values, sulfide levels and nitrogen sources were tested and evaluated for the two enrichments. The MOB-SOB culture gave promising results in terms of both biomass yield (up to 0.07±0.01 g VSS/g CH4-COD) and protein content (up to 73±5% of VSS) at 1500 ppm of equivalent H2S. The latter enrichment was able to grow also under acidic pH (5.8-7.0), but as inhibited outside the optimal CH4:O2 ratio of 2:3. The obtained results show the capability of MOB-SOB mixed-cultures to directly upcycle sulfide-rich biogas into microbial protein potentially suited for feed, food or biobased product applications.
Collapse
Affiliation(s)
- Marica Areniello
- Department of Microbiology and Ryan Institute, School of Natural Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland.
| | - Silvio Matassa
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio, Naples, 80125, Italy
| | - Giovanni Esposito
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio, Naples, 80125, Italy
| | - Piet N L Lens
- Department of Microbiology and Ryan Institute, School of Natural Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
| |
Collapse
|
11
|
Naizabekov S, Hyun SW, Na JG, Yoon S, Lee OK, Lee EY. Comparative genomic analysis of Methylocystis sp. MJC1 as a platform strain for polyhydroxybutyrate biosynthesis. PLoS One 2023; 18:e0284846. [PMID: 37163531 PMCID: PMC10171618 DOI: 10.1371/journal.pone.0284846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/06/2023] [Indexed: 05/12/2023] Open
Abstract
Biodegradable polyhydroxybutyrate (PHB) can be produced from methane by some type II methanotroph such as the genus Methylocystis. This study presents the comparative genomic analysis of a newly isolated methanotroph, Methylocystis sp. MJC1 as a biodegradable PHB-producing platform strain. Methylocystis sp. MJC1 accumulates up to 44.5% of PHB based on dry cell weight under nitrogen-limiting conditions. To facilitate its development as a PHB-producing platform strain, the complete genome sequence of Methylocystis sp. MJC1 was assembled, functionally annotated, and compared with genomes of other Methylocystis species. Phylogenetic analysis has shown that Methylocystis parvus to be the closest species to Methylocystis sp. MJC1. Genome functional annotation revealed that Methylocystis sp. MJC1 contains all major type II methanotroph biochemical pathways such as the serine cycle, EMC pathway, and Krebs cycle. Interestingly, Methylocystis sp. MJC1 has both particulate and soluble methane monooxygenases, which are not commonly found among Methylocystis species. In addition, this species also possesses most of the RuMP pathway reactions, a characteristic of type I methanotrophs, and all PHB biosynthetic genes. These comparative analysis would open the possibility of future practical applications such as the development of organism-specific genome-scale models and application of metabolic engineering strategies to Methylocystis sp. MJC1.
Collapse
Affiliation(s)
- Sanzhar Naizabekov
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Seung Woon Hyun
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Sukhwan Yoon
- Department of Civil & Environmental Engineering, Korea Advanced Institute of Science & Technology, Daejeon, Republic of Korea
| | - Ok Kyung Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| |
Collapse
|
12
|
Huang X, Song Q, Guo S, Fei Q. Transcription regulation strategies in methylotrophs: progress and challenges. BIORESOUR BIOPROCESS 2022; 9:126. [PMID: 38647763 PMCID: PMC10992012 DOI: 10.1186/s40643-022-00614-3] [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: 08/30/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022] Open
Abstract
As a promising industrial microorganism, methylotroph is capable of using methane or methanol as the sole carbon source natively, which has been utilized in the biosynthesis of various bioproducts. However, the relatively low efficiency of carbon conversion has become a limiting factor throughout the development of methanotrophic cell factories due to the unclear genetic background. To better highlight their advantages in methane or methanol-based biomanufacturing, some metabolic engineering strategies, including upstream transcription regulation projects, are being popularized in methylotrophs. In this review, several strategies of transcription regulations applied in methylotrophs are summarized and their applications are discussed and prospected.
Collapse
Affiliation(s)
- Xiaohan Huang
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Qiaoqiao Song
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Shuqi Guo
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Qiang Fei
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
- Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Jiaotong University, Xi'an, 710049, China.
| |
Collapse
|
13
|
Guo K, Hakobyan A, Glatter T, Paczia N, Liesack W. Methylocystis sp. Strain SC2 Acclimatizes to Increasing NH 4+ Levels by a Precise Rebalancing of Enzymes and Osmolyte Composition. mSystems 2022; 7:e0040322. [PMID: 36154142 PMCID: PMC9600857 DOI: 10.1128/msystems.00403-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/26/2022] [Indexed: 12/24/2022] Open
Abstract
A high NH4+ load is known to inhibit bacterial methane oxidation. This is due to a competition between CH4 and NH3 for the active site of particulate methane monooxygenase (pMMO), which converts CH4 to CH3OH. Here, we combined global proteomics with amino acid profiling and nitrogen oxides measurements to elucidate the cellular acclimatization response of Methylocystis sp. strain SC2 to high NH4+ levels. Relative to 1 mM NH4+, a high (50 mM and 75 mM) NH4+ load under CH4-replete conditions significantly increased the lag phase duration required for proteome adjustment. The number of differentially regulated proteins was highly significantly correlated with an increasing NH4+ load. The cellular responses to increasing ionic and osmotic stress involved a significant upregulation of stress-responsive proteins, the K+ "salt-in" strategy, the synthesis of compatible solutes (glutamate and proline), and the induction of the glutathione metabolism pathway. A significant increase in the apparent Km value for CH4 oxidation during the growth phase was indicative of increased pMMO-based oxidation of NH3 to toxic hydroxylamine. The detoxifying activity of hydroxlyamine oxidoreductase (HAO) led to a significant accumulation of NO2- and, upon decreasing O2 tension, N2O. Nitric oxide reductase and hybrid cluster proteins (Hcps) were the candidate enzymes for the production of N2O. In summary, strain SC2 has the capacity to precisely rebalance enzymes and osmolyte composition in response to increasing NH4+ exposure, but the need to simultaneously combat both ionic-osmotic stress and the toxic effects of hydroxylamine may be the reason why its acclimatization capacity is limited to 75 mM NH4+. IMPORTANCE In addition to reducing CH4 emissions from wetlands and landfills, the activity of alphaproteobacterial methane oxidizers of the genus Methylocystis contributes to the sink capacity of forest and grassland soils for atmospheric methane. The methane-oxidizing activity of Methylocystis spp. is, however, sensitive to high NH4+ concentrations. This is due to the competition of CH4 and NH3 for the active site of particulate methane monooxygenase, thereby resulting in the production of toxic hydroxylamine with an increasing NH4+ load. An understanding of the physiological and molecular response mechanisms of Methylocystis spp. is therefore of great importance. Here, we combined global proteomics with amino acid profiling and NOx measurements to disentangle the cellular mechanisms underlying the acclimatization of Methylocystis sp. strain SC2 to an increasing NH4+ load.
Collapse
Affiliation(s)
- Kangli Guo
- Methanotrophic Bacteria and Environmental Genomics/Transcriptomics Research Group, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Anna Hakobyan
- 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
| |
Collapse
|
14
|
Millar EN, Kidd KA, Surette MG, Bennett CJ, Salerno J, Gillis PL. Effects of municipal wastewater effluents on the digestive gland microbiome of wild freshwater mussels (Lasmigona costata). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 241:113774. [PMID: 35777341 DOI: 10.1016/j.ecoenv.2022.113774] [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: 03/01/2022] [Revised: 06/07/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Gut microbial communities are vital for maintaining host health, and are sensitive to diet, environment, and chemical exposures. Wastewater treatment plants (WWTPs) release effluents containing antimicrobials, pharmaceuticals, and other contaminants that may negatively affect the gut microbiome of downstream organisms. This study investigated changes in the diversity and composition of the digestive gland microbiome of flutedshell mussels (Lasmigona costata) from upstream and downstream of two large (service >100,000) WWTPs. Mussel digestive gland microbiome was analyzed following the extraction, PCR amplification, and sequencing of bacterial DNA using the V3-V4 hypervariable regions of the 16 S rRNA gene. Bacterial alpha diversity decreased at sites downstream of the second WWTP and these sites were dissimilar in beta diversity from sites upstream and downstream of the first upstream WWTP. The microbiomes of mussels collected downstream of the first WWTP had increased relative abundances of Actinobacteria, Bacteroidetes, and Firmicutes, with a decrease in Cyanobacteria, compared to upstream mussels. Meanwhile, those collected downstream of the second WWTP increased in Proteobacteria and decreased in Actinobacteria, Bacteroidetes, and Tenericutes. Increased Proteobacteria has been linked to adverse effects in mammals, but their functions in mussels is currently unknown. Finally, effluent-derived bacteria were found in the microbiome of mussels downstream of both WWTPs but not in those from upstream. Overall, results show that the digestive gland microbiome of mussels collected upstream and downstream of WWTPs differed, which has implications for altered host health and the transport of WWTP-derived bacteria through aquatic ecosystems.
Collapse
Affiliation(s)
- Elise N Millar
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Karen A Kidd
- Department of Biology, McMaster University, Hamilton, Ontario, Canada; School of Earth, Environment and Society, McMaster University, Hamilton, Ontario, Canada.
| | - Michael G Surette
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada; Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - C James Bennett
- Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Joseph Salerno
- Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, Ontario, Canada
| | - Patricia L Gillis
- Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, Burlington, Ontario, Canada
| |
Collapse
|
15
|
Steinsdóttir HGR, Schauberger C, Mhatre S, Thamdrup B, Bristow LA. Aerobic and anaerobic methane oxidation in a seasonally anoxic basin. LIMNOLOGY AND OCEANOGRAPHY 2022; 67:1257-1273. [PMID: 36248250 PMCID: PMC9540798 DOI: 10.1002/lno.12074] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 02/14/2022] [Accepted: 03/14/2022] [Indexed: 06/16/2023]
Abstract
Shallow coastal waters are dynamic environments that dominate global marine methane emissions. Particularly high methane concentrations are found in seasonally anoxic waters, which are spreading in eutrophic coastal systems, potentially leading to increased methane emissions to the atmosphere. Here we explore how the seasonal development of anoxia influenced methane concentrations, rates of methane oxidation, and the community composition of methanotrophs in the shallow eutrophic water column of Mariager Fjord, Denmark. Our results show the development of steep concentration gradients toward the oxic-anoxic interface as methane accumulated to 1.4 μM in anoxic bottom waters. Yet, the fjord possessed an efficient microbial methane filter near the oxic-anoxic interface that responded to the increasing methane flux. In experimental incubations, methane oxidation near the oxic-anoxic interface proceeded both aerobically and anaerobically with nearly equal efficiency reaching turnover rates as high as 0.6 and 0.8 d-1, respectively, and was seemingly mediated by members of the Methylococcales belonging to the Deep Sea-1 clade. Throughout the period, both aerobic and anaerobic methane oxidation rates were high enough to consume the estimated methane flux. Thus, our results indicate that seasonal anoxia did not increase methane emissions.
Collapse
Affiliation(s)
| | | | - Snehit Mhatre
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| | - Bo Thamdrup
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| | - Laura A. Bristow
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| |
Collapse
|
16
|
Steinsdóttir HGR, Gómez‐Ramírez E, Mhatre S, Schauberger C, Bertagnolli AD, Pratte ZA, Stewart FJ, Thamdrup B, Bristow LA. Anaerobic methane oxidation in a coastal oxygen minimum zone: spatial and temporal dynamics. Environ Microbiol 2022; 24:2361-2379. [PMID: 35415879 PMCID: PMC9323439 DOI: 10.1111/1462-2920.16003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 04/05/2022] [Accepted: 04/05/2022] [Indexed: 11/28/2022]
Abstract
Coastal waters are a major source of marine methane to the atmosphere. Particularly high concentrations of this potent greenhouse gas are found in anoxic waters, but it remains unclear if and to what extent anaerobic methanotrophs mitigate the methane flux. Here we investigate the long-term dynamics in methanotrophic activity and the methanotroph community in the coastal oxygen minimum zone (OMZ) of Golfo Dulce, Costa Rica, combining biogeochemical analyses, experimental incubations and 16S rRNA gene sequencing over 3 consecutive years. Our results demonstrate a stable redox zonation across the years with high concentrations of methane (up to 1.7 μmol L-1 ) in anoxic bottom waters. However, we also measured high activities of anaerobic methane oxidation in the OMZ core (rate constant, k, averaging 30 yr-1 in 2018 and 8 yr-1 in 2019-2020). The OPU3 and Deep Sea-1 clades of the Methylococcales were implicated as conveyors of the activity, peaking in relative abundance 5-25 m below the oxic-anoxic interface and in the deep anoxic water respectively. Although their genetic capacity for anaerobic methane oxidation remains unexplored, their sustained high relative abundance indicates an adaptation of these clades to the anoxic, methane-rich OMZ environment, allowing them to play major roles in mitigating methane fluxes.
Collapse
Affiliation(s)
| | | | - Snehit Mhatre
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| | | | | | - Zoe A. Pratte
- Department of Microbiology and Cell BiologyMontana State UniversityBozemanMTUSA
| | - Frank J. Stewart
- Department of Microbiology and Cell BiologyMontana State UniversityBozemanMTUSA
- School of Biological SciencesCenter for Microbial Dynamics and Infection, Georgia Institute of TechnologyAtlantaGAUSA
| | - Bo Thamdrup
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| | - Laura A. Bristow
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
| |
Collapse
|
17
|
Low N 2O and variable CH 4 fluxes from tropical forest soils of the Congo Basin. Nat Commun 2022; 13:330. [PMID: 35039512 PMCID: PMC8764088 DOI: 10.1038/s41467-022-27978-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 12/21/2021] [Indexed: 12/18/2022] Open
Abstract
Globally, tropical forests are assumed to be an important source of atmospheric nitrous oxide (N2O) and sink for methane (CH4). Yet, although the Congo Basin comprises the second largest tropical forest and is considered the most pristine large basin left on Earth, in situ N2O and CH4 flux measurements are scarce. Here, we provide multi-year data derived from on-ground soil flux (n = 1558) and riverine dissolved gas concentration (n = 332) measurements spanning montane, swamp, and lowland forests. Each forest type core monitoring site was sampled at least for one hydrological year between 2016 - 2020 at a frequency of 7-14 days. We estimate a terrestrial CH4 uptake (in kg CH4-C ha−1 yr−1) for montane (−4.28) and lowland forests (−3.52) and a massive CH4 release from swamp forests (non-inundated 2.68; inundated 341). All investigated forest types were a N2O source (except for inundated swamp forest) with 0.93, 1.56, 3.5, and −0.19 kg N2O-N ha−1 yr−1 for montane, lowland, non-inundated swamp, and inundated swamp forests, respectively. The Congo Basin is home to the second largest stretch of continuous tropical forest, but the magnitude of greenhouse fluxes are poorly understood. Here the authors analyze gas samples and find the region is not actually a hotspot of N2O emissions.
Collapse
|
18
|
Lazic M, Sugden S, Sauvageau D, Stein LY. Metabolome profiles of the alphaproteobacterial methanotroph Methylocystis sp. Rockwell in response to carbon and nitrogen source. FEMS Microbiol Lett 2021; 368:6055661. [PMID: 33378457 DOI: 10.1093/femsle/fnaa219] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/28/2020] [Indexed: 01/23/2023] Open
Abstract
Methanotrophs use methane as a sole carbon source and thus play a critical role in its global consumption. Intensified interest in methanotrophs for their low-cost production of value-added products and large-scale industrialization has led to investigations of strain-to-strain variation in parameters for growth optimization and metabolic regulation. In this study, Methylocystis sp. Rockwell was grown with methane or methanol as a carbon source and ammonium or nitrate as a nitrogen source. The intracellular metabolomes and production of polyhydroxybutyrate, a bioplastic precursor, were compared among treatments to determine how the different combinations of carbon and nitrogen sources affected metabolite production. The methane-ammonium condition resulted in the highest growth, followed by the methane-nitrate, methanol-nitrate and methanol-ammonium conditions. Overall, the methane-ammonium and methane-nitrate conditions directed metabolism toward energy-conserving pathways, while methanol-ammonium and methanol-nitrate directed the metabolic response toward starvation pathways. Polyhydroxybutyrate was produced at greater abundances in methanol-grown cells, independent of the nitrogen source. Together, the results revealed how Methylocystis sp. Rockwell altered its metabolism with different combinations of carbon and nitrogen source, with implications for production of industrially relevant metabolites.
Collapse
Affiliation(s)
- Marina Lazic
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Scott Sugden
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Dominic Sauvageau
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada
| | - Lisa Y Stein
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
19
|
Nguyen DTN, Lee OK, Nguyen TT, Lee EY. Type II methanotrophs: A promising microbial cell-factory platform for bioconversion of methane to chemicals. Biotechnol Adv 2021; 47:107700. [PMID: 33548453 DOI: 10.1016/j.biotechadv.2021.107700] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/04/2020] [Accepted: 01/20/2021] [Indexed: 10/22/2022]
Abstract
Methane, the predominant element in natural gas and biogas, represents a promising alternative to carbon feedstocks in the biotechnological industry due to its low cost and high abundance. The bioconversion of methane to value-added products can enhance the value of gas and mitigate greenhouse gas emissions. Methanotrophs, methane-utilizing bacteria, can make a significant contribution to the production of various valuable biofuels and chemicals from methane. Type II methanotrophs in comparison with Type I methanotrophs have distinct advantages, including high acetyl-CoA flux and the co-incorporation of two important greenhouse gases (methane and CO2), making it a potential microbial cell-factory platform for methane-derived biomanufacturing. Herein, we review the most recent advances in Type II methanotrophs related to multi-omics studies and metabolic engineering. Representative examples and prospects of metabolic engineering strategies for the production of suitable products are also discussed.
Collapse
Affiliation(s)
- Diep Thi Ngoc Nguyen
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Gyeonggi-do 17104, Republic of Korea
| | - Ok Kyung Lee
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Gyeonggi-do 17104, Republic of Korea
| | - Thu Thi Nguyen
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Gyeonggi-do 17104, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (Integrated Engineering), Kyung Hee University, Gyeonggi-do 17104, Republic of Korea.
| |
Collapse
|
20
|
Enhancement of nitrous oxide emissions in soil microbial consortia via copper competition between proteobacterial methanotrophs and denitrifiers. Appl Environ Microbiol 2020; 87:e0230120. [PMID: 33355098 DOI: 10.1128/aem.02301-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Unique means of copper scavenging have been identified in proteobacterial methanotrophs, particularly the use of methanobactin, a novel ribosomally synthesized post-translationally modified polypeptide that binds copper with very high affinity. The possibility that copper sequestration strategies of methanotrophs may interfere with copper uptake of denitrifiers in situ and thereby enhance N2O emissions was examined using a suite of laboratory experiments performed with rice paddy microbial consortia. Addition of purified methanobactin from Methylosinus trichosporium OB3b to denitrifying rice paddy soil microbial consortia resulted in substantially increased N2O production, with more pronounced responses observed for soils with lower copper content. The N2O emission-enhancing effect of the soil's native mbnA-expressing Methylocystaceae methanotrophs on the native denitrifiers was then experimentally verified with a Methylocystaceae-dominant chemostat culture prepared from a rice paddy microbial consortium as the inoculum. Lastly, with microcosms amended with varying cell numbers of methanobactin-producing Methylosinus trichosporium OB3b before CH4 enrichment, microbiomes with different ratios of methanobactin-producing Methylocystaceae to gammaproteobacterial methanotrophs incapable of methanobactin production were simulated. Significant enhancement of N2O production from denitrification was evident in both Methylocystaceae-dominant and Methylococcaceae-dominant enrichments, albeit to a greater extent in the former, signifying the comparative potency of methanobactin-mediated copper sequestration while implying the presence of alternative copper abstraction mechanisms for Methylococcaceae These observations support that copper-mediated methanotrophic enhancement of N2O production from denitrification is plausible where methanotrophs and denitrifiers cohabit.IMPORTANCE Proteobacterial methanotrophs, groups of microorganisms that utilize methane as source of energy and carbon, have been known to utilize unique mechanisms to scavenge copper, namely utilization of methanobactin, a polypeptide that binds copper with high affinity and specificity. Previously the possibility that copper sequestration by methanotrophs may lead to alteration of cuproenzyme-mediated reactions in denitrifiers and consequently increase emission of potent greenhouse gas N2O has been suggested in axenic and co-culture experiments. Here, a suite of experiments with rice paddy soil slurry cultures with complex microbial compositions were performed to corroborate that such copper-mediated interplay may actually take place in environments co-habited by diverse methanotrophs and denitrifiers. As spatial and temporal heterogeneity allow for spatial coexistence of methanotrophy (aerobic) and denitrification (anaerobic) in soils, the results from this study suggest that this previously unidentified mechanism of N2O production may account for significant proportion of N2O efflux from agricultural soils.
Collapse
|
21
|
Jung GY, Rhee SK, Han YS, Kim SJ. Genomic and Physiological Properties of a Facultative Methane-Oxidizing Bacterial Strain of Methylocystis sp. from a Wetland. Microorganisms 2020; 8:microorganisms8111719. [PMID: 33147874 PMCID: PMC7716213 DOI: 10.3390/microorganisms8111719] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/23/2020] [Accepted: 10/30/2020] [Indexed: 01/07/2023] Open
Abstract
Methane-oxidizing bacteria are crucial players in controlling methane emissions. This study aimed to isolate and characterize a novel wetland methanotroph to reveal its role in the wetland environment based on genomic information. Based on phylogenomic analysis, the isolated strain, designated as B8, is a novel species in the genus Methylocystis. Strain B8 grew in a temperature range of 15 °C to 37 °C (optimum 30–35 °C) and a pH range of 6.5 to 10 (optimum 8.5–9). Methane, methanol, and acetate were used as carbon sources. Hydrogen was produced under oxygen-limited conditions. The assembled genome comprised of 3.39 Mbp and 59.9 mol% G + C content. The genome contained two types of particulate methane monooxygenases (pMMO) for low-affinity methane oxidation (pMMO1) and high-affinity methane oxidation (pMMO2). It was revealed that strain B8 might survive atmospheric methane concentration. Furthermore, the genome had various genes for hydrogenase, nitrogen fixation, polyhydroxybutyrate synthesis, and heavy metal resistance. This metabolic versatility of strain B8 might enable its survival in wetland environments.
Collapse
Affiliation(s)
- Gi-Yong Jung
- Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Korea;
- Department of Microbiology, Chungbuk National University, Cheongju 28644, Korea;
| | - Sung-Keun Rhee
- Department of Microbiology, Chungbuk National University, Cheongju 28644, Korea;
| | - Young-Soo Han
- Department of Environmental Engineering, Chungnam National University, Daejeon 34134, Korea;
| | - So-Jeong Kim
- Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Korea;
- Correspondence: ; Tel.: +82-42-868-3311; Fax: +82-42-868-3414
| |
Collapse
|
22
|
Farhan Ul Haque M, Xu HJ, Murrell JC, Crombie A. Facultative methanotrophs - diversity, genetics, molecular ecology and biotechnological potential: a mini-review. MICROBIOLOGY (READING, ENGLAND) 2020; 166:894-908. [PMID: 33085587 PMCID: PMC7660913 DOI: 10.1099/mic.0.000977] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/20/2020] [Indexed: 12/18/2022]
Abstract
Methane-oxidizing bacteria (methanotrophs) play a vital role in reducing atmospheric methane emissions, and hence mitigating their potent global warming effects. A significant proportion of the methane released is thermogenic natural gas, containing associated short-chain alkanes as well as methane. It was one hundred years following the description of methanotrophs that facultative strains were discovered and validly described. These can use some multi-carbon compounds in addition to methane, often small organic acids, such as acetate, or ethanol, although Methylocella strains can also use short-chain alkanes, presumably deriving a competitive advantage from this metabolic versatility. Here, we review the diversity and molecular ecology of facultative methanotrophs. We discuss the genetic potential of the known strains and outline the consequent benefits they may obtain. Finally, we review the biotechnological promise of these fascinating microbes.
Collapse
Affiliation(s)
| | - Hui-Juan Xu
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: Joint Institute for Environmental Research & Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China
| | - J. Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andrew Crombie
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| |
Collapse
|
23
|
Changes in Methane Emission and Community Composition of Methane-Cycling Microorganisms Along an Elevation Gradient in the Dongting Lake Floodplain, China. ATMOSPHERE 2020. [DOI: 10.3390/atmos11090997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Methane (CH4) emission and environmental controls of CH4-cycling microorganisms are unclear in inland floodplains. Here, we examined soil CH4 emissions and the community composition of CH4-cycling microorganisms under three vegetation types—mudflat (MF, no vegetation cover), Carex meadow (CM, mainly Carex brevicuspis), and reed land (RL, mainly Miscanthus sacchariflorus)—from water-adjacent areas to higher-elevation land in the Dongting Lake floodplain, China. The results showed that CH4 emission is the highest in CM, while significant absorption was observed in the RL site. The abundance ratio of methanogen/methanotroph was the highest in CM, intermediate in MF, and lowest in RL. The Methanosarcinaceae family represented the dominant methanogens in the three sampling sites (41.32–75.25%). The genus Methylocystis (60.85%, type II methanotrophs) was dominant in CM, while Methylobacter and Methylosarcina (type I methanotrophs) were the dominant genera in MF (51.00%) and RL (50.24%), respectively. Structural equation model analysis showed that methanogen and methanotroph abundance were affected by water table depth, soil water content, and pH indirectly through soil organic content, total nitrogen, microbial biomass carbon, and microbial biomass nitrogen. These results indicated that the Dongting Lake floodplain may change from a CH4 source to a CH4 sink with vegetation succession with an increase in elevation, and the methanogen/methanotroph ratio can be used as a proxy for CH4 emission in wetland soils. The continuous increase in reed area combined with the decrease in Carex meadow may mitigate CH4 emission and enhance the CH4 sink function during the non-flood season in the Dongting Lake floodplain.
Collapse
|
24
|
Hakobyan A, Zhu J, Glatter T, Paczia N, Liesack W. Hydrogen utilization by Methylocystis sp. strain SC2 expands the known metabolic versatility of type IIa methanotrophs. Metab Eng 2020; 61:181-196. [PMID: 32479801 DOI: 10.1016/j.ymben.2020.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/20/2020] [Accepted: 05/01/2020] [Indexed: 12/19/2022]
Abstract
Methane, a non-expensive natural substrate, is used by Methylocystis spp. as a sole source of carbon and energy. Here, we assessed whether Methylocystis sp. strain SC2 is able to also utilize hydrogen as an energy source. The addition of 2% H2 to the culture headspace had the most significant positive effect on the growth yield under CH4 (6%) and O2 (3%) limited conditions. The SC2 biomass yield doubled from 6.41 (±0.52) to 13.82 (±0.69) mg cell dry weight per mmol CH4, while CH4 consumption was significantly reduced. Regardless of H2 addition, CH4 utilization was increasingly redirected from respiration to fermentation-based pathways with decreasing O2/CH4 mixing ratios. Theoretical thermodynamic calculations confirmed that hydrogen utilization under oxygen-limited conditions doubles the maximum biomass yield compared to fully aerobic conditions without H2 addition. Hydrogen utilization was linked to significant changes in the SC2 proteome. In addition to hydrogenase accessory proteins, the production of Group 1d and Group 2b hydrogenases was significantly increased in both short- and long-term incubations. Both long-term incubation with H2 (37 d) and treatments with chemical inhibitors revealed that SC2 growth under hydrogen-utilizing conditions does not require the activity of complex I. Apparently, strain SC2 has the metabolic capacity to channel hydrogen-derived electrons into the quinone pool, which provides a link between hydrogen oxidation and energy production. In summary, H2 may be a promising alternative energy source in biotechnologically oriented methanotroph projects that aim to maximize biomass yield from CH4, such as the production of high-quality feed protein.
Collapse
Affiliation(s)
- Anna Hakobyan
- Research Group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Jing Zhu
- Research Group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; Institute of Environmental Science and Technology, Zhejiang University, Hangzhou, China
| | - 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
- Research Group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany.
| |
Collapse
|
25
|
Weingarten EA, Atkinson CL, Jackson CR. The gut microbiome of freshwater Unionidae mussels is determined by host species and is selectively retained from filtered seston. PLoS One 2019; 14:e0224796. [PMID: 31721801 PMCID: PMC6853330 DOI: 10.1371/journal.pone.0224796] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/22/2019] [Indexed: 01/06/2023] Open
Abstract
Freshwater mussels are a species-rich group of aquatic invertebrates that are among the most endangered groups of fauna worldwide. As filter-feeders that are constantly exposed to new microbial inoculants, mussels represent an ideal system to investigate the effects of species or the environment on gut microbiome composition. In this study, we examined if host species or site exerts a greater influence on microbiome composition. Individuals of four co-occurring freshwater mussel species, Cyclonaias asperata, Fusconaia cerina, Lampsilis ornata, and Obovaria unicolor were collected from six sites along a 50 km stretch of the Sipsey River in Alabama, USA. High throughput 16S rRNA gene sequencing revealed that mussel gut bacterial microbiota were distinct from bacteria on seston suspended in the water column, and that the composition of the gut microbiota was influenced by both host species and site. Despite species and environmental variation, the most frequently detected sequences within the mussel microbiota were identified as members of the Clostridiales. Sequences identified as the nitrogen-fixing taxon Methylocystis sp. were also abundant in all mussel species, and sequences of both bacterial taxa were more abundant in mussels than in water. Site physicochemical conditions explained almost 45% of variation in seston bacterial communities but less than 8% of variation in the mussel bacterial microbiome. Together, these findings suggest selective retention of bacterial taxa by the freshwater mussel host, and that both species and the environment are important in determining mussel gut microbiome composition.
Collapse
Affiliation(s)
- Eric A. Weingarten
- Department of Biology, University of Mississippi, University, Mississippi, United States of America
| | - Carla L. Atkinson
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, United States of America
| | - Colin R. Jackson
- Department of Biology, University of Mississippi, University, Mississippi, United States of America
| |
Collapse
|
26
|
Bordel S, Rodríguez Y, Hakobyan A, Rodríguez E, Lebrero R, Muñoz R. Genome scale metabolic modeling reveals the metabolic potential of three Type II methanotrophs of the genus Methylocystis. Metab Eng 2019; 54:191-199. [DOI: 10.1016/j.ymben.2019.04.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 12/19/2022]
|
27
|
Bordel S, Rojas A, Muñoz R. Reconstruction of a Genome Scale Metabolic Model of the polyhydroxybutyrate producing methanotroph Methylocystis parvus OBBP. Microb Cell Fact 2019; 18:104. [PMID: 31170985 PMCID: PMC6554988 DOI: 10.1186/s12934-019-1154-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 06/01/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Methylocystis parvus is a type II methanotroph characterized by its high specific methane degradation rate (compared to other methanotrophs of the same family) and its ability to accumulate up to 50% of its biomass in the form of poly-3-hydroxybutyrate (PHB) under nitrogen limiting conditions. This makes it a very promising cell factory. RESULTS This article reports the first Genome Scale Metabolic Model of M. parvus OBBP. The model is compared to Genome Scale Metabolic Models of the closely related methanotrophs Methylocystis hirsuta and Methylocystis sp. SC2. Using the reconstructed model, it was possible to predict the biomass yield of M. parvus on methane. The prediction was consistent with the observed experimental yield, under the assumption of the so called "redox arm mechanism" for methane oxidation. The co-consumption of stored PHB and methane was also modeled, leading to accurate predictions of biomass yields and oxygen consumption rates and revealing an anaplerotic role of PHB degradation. Finally, the model revealed that anoxic PHB consumption has to be coupled to denitrification, as no fermentation of PHB is allowed by the reconstructed metabolic model. CONCLUSIONS The "redox arm" mechanism appears to be a general characteristic of type II methanotrophs, versus type I methanotrophs that use the "direct coupling" mechanism. The co-consumption of stored PHB and methane was predicted to play an anaplerotic role replenishing the serine cycle with glyoxylate and the TCA cycle with succinyl-CoA, which allows the withdrawal of metabolic precursors for biosynthesis. The stored PHB can be also used as an energy source under anoxic conditions when coupled to denitrification.
Collapse
Affiliation(s)
- Sergio Bordel
- Departamento de Ingeniería Química y Tecnología del medio ambiente, Escuela de Ingenierías Industriales, Universidad de Valladolid, Valladolid, Spain.
- Institute of Sustainable Processes, Universidad de Valladolid, Valladolid, Spain.
| | - Antonia Rojas
- Biopolis S.L., Parc Cientific Universitat de Valencia, Paterna, Spain
| | - Raúl Muñoz
- Departamento de Ingeniería Química y Tecnología del medio ambiente, Escuela de Ingenierías Industriales, Universidad de Valladolid, Valladolid, Spain
- Institute of Sustainable Processes, Universidad de Valladolid, Valladolid, Spain
| |
Collapse
|
28
|
Szafranek-Nakonieczna A, Wolińska A, Zielenkiewicz U, Kowalczyk A, Stępniewska Z, Błaszczyk M. Activity and Identification of Methanotrophic Bacteria in Arable and No-Tillage Soils from Lublin Region (Poland). MICROBIAL ECOLOGY 2019; 77:701-712. [PMID: 30171270 PMCID: PMC6469817 DOI: 10.1007/s00248-018-1248-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/20/2018] [Indexed: 06/08/2023]
Abstract
Methanotrophic bacteria are able to use methane (CH4) as a sole carbon and energy source. Photochemical oxidation of methane takes place in the stratosphere, whereas in the troposphere, this process is carried out by methanotrophic bacteria. On the one hand, it is known that the efficiency of biological CH4 oxidation is dependent on the mode of land use but, on the other hand, the knowledge of this impact on methanotrophic activity (MTA) is still limited. Thus, the aim of the study was to determine the CH4 oxidation ability of methanotrophic bacteria inhabiting selected arable and no-tillage soils from the Lublin region (Albic Luvisol, Brunic Arenosol, Haplic Chernozem, Calcaric Cambisol) and to identify bacteria involved in this process. MTA was determined based on incubation of soils in air with addition of methane at the concentrations of 0.002, 0.5, 1, 5, and 10%. The experiment was conducted in a temperature range of 10-30 °C. Methanotrophs in soils were identified by next-generation sequencing (NGS). MTA was confirmed in all investigated soils (in the entire range of the tested methane concentrations and temperatures, except for the arable Albic Luvisol). Importantly, the MTA values in the no-tillage soil were nearly two-fold higher than in the cultivated soils. Statistical analysis indicated a significant influence of land use, type of soil, temperature, and especially methane concentration (p < 0.05) on MTA. Metagenomic analysis confirmed the presence of methanotrophs from the genus Methylocystis (Alphaproteobacteria) in the studied soils (except for the arable Albic Luvisol). Our results also proved the ability of methanotrophic bacteria to oxidize methane although they constituted only up to 0.1% of the total bacterial community.
Collapse
Affiliation(s)
- Anna Szafranek-Nakonieczna
- Department of Biochemistry and Environmental Chemistry, Institute of Biotechnology, The John Paul II Catholic University of Lublin, 1 I Konstantynów Str, 20-708, Lublin, Poland.
| | - Agnieszka Wolińska
- Department of Biochemistry and Environmental Chemistry, Institute of Biotechnology, The John Paul II Catholic University of Lublin, 1 I Konstantynów Str, 20-708, Lublin, Poland
| | - Urszula Zielenkiewicz
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics PAS, 5a Pawińskiego Str, 02-106, Warsaw, Poland
| | - Agnieszka Kowalczyk
- Department of Biochemistry and Environmental Chemistry, Institute of Biotechnology, The John Paul II Catholic University of Lublin, 1 I Konstantynów Str, 20-708, Lublin, Poland
| | - Zofia Stępniewska
- Department of Biochemistry and Environmental Chemistry, Institute of Biotechnology, The John Paul II Catholic University of Lublin, 1 I Konstantynów Str, 20-708, Lublin, Poland
| | - Mieczysław Błaszczyk
- Department of Microbial Biology, Warsaw University of Life Sciences, Nowoursynowska 159 Str, 02-776, Warsaw, Poland
| |
Collapse
|
29
|
Bodelier PLE, Pérez G, Veraart AJ, Krause SMB. Methanotroph Ecology, Environmental Distribution and Functioning. METHANOTROPHS 2019. [DOI: 10.1007/978-3-030-23261-0_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
30
|
Bordel S, Rodríguez E, Muñoz R. Genome sequence of Methylocystis hirsuta CSC1, a polyhydroxyalkanoate producing methanotroph. Microbiologyopen 2018; 8:e00771. [PMID: 30548837 PMCID: PMC6562138 DOI: 10.1002/mbo3.771] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/23/2018] [Accepted: 10/26/2018] [Indexed: 01/22/2023] Open
Abstract
Polyhydroxyalkanoates (PHAs) are biodegradable plastics that can be produced by some methanotrophic organisms such as those of the genus Methylocystis. This allows the conversion of a detrimental greenhouse gas into an environmentally friendly high added‐value bioproduct. This study presents the genome sequence of Methylocystis hirsuta CSC1 (a high yield PHB producer). The genome comprises 4,213,043 bp in 4 contigs, with the largest contig being 3,776,027 bp long. Two of the other contigs are likely to correspond to large size plasmids. A total of 4,664 coding sequences were annotated, revealing a PHA production cluster, two distinct particulate methane monooxygenases with active catalytic sites, as well as a nitrogen fixation operon and a partial denitrification pathway.
Collapse
Affiliation(s)
- Sergio Bordel
- Departamento de Ingeniería Química y Tecnología del Medio Ambiente, Escuela de Ingenierías IndustrialesUniversidad de ValladolidValladolidSpain
- Institute of Sustainable ProcessesUniversidad de ValladolidValladolidSpain
| | - Elisa Rodríguez
- Departamento de Ingeniería Química y Tecnología del Medio Ambiente, Escuela de Ingenierías IndustrialesUniversidad de ValladolidValladolidSpain
- Institute of Sustainable ProcessesUniversidad de ValladolidValladolidSpain
| | - Raúl Muñoz
- Departamento de Ingeniería Química y Tecnología del Medio Ambiente, Escuela de Ingenierías IndustrialesUniversidad de ValladolidValladolidSpain
- Institute of Sustainable ProcessesUniversidad de ValladolidValladolidSpain
| |
Collapse
|
31
|
Yu WJ, Lee JW, Nguyen NL, Rhee SK, Park SJ. The characteristics and comparative analysis of methanotrophs reveal genomic insights into Methylomicrobium sp. enriched from marine sediments. Syst Appl Microbiol 2018; 41:415-426. [DOI: 10.1016/j.syapm.2018.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 05/04/2018] [Accepted: 05/04/2018] [Indexed: 10/16/2022]
|
32
|
Nguyen NL, Yu WJ, Gwak JH, Kim SJ, Park SJ, Herbold CW, Kim JG, Jung MY, Rhee SK. Genomic Insights Into the Acid Adaptation of Novel Methanotrophs Enriched From Acidic Forest Soils. Front Microbiol 2018; 9:1982. [PMID: 30210468 PMCID: PMC6119699 DOI: 10.3389/fmicb.2018.01982] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/06/2018] [Indexed: 01/08/2023] Open
Abstract
Soil acidification is accelerated by anthropogenic and agricultural activities, which could significantly affect global methane cycles. However, detailed knowledge of the genomic properties of methanotrophs adapted to acidic soils remains scarce. Using metagenomic approaches, we analyzed methane-utilizing communities enriched from acidic forest soils with pH 3 and 4, and recovered near-complete genomes of proteobacterial methanotrophs. Novel methanotroph genomes designated KS32 and KS41, belonging to two representative clades of methanotrophs (Methylocystis of Alphaproteobacteria and Methylobacter of Gammaproteobacteria), were dominant. Comparative genomic analysis revealed diverse systems of membrane transporters for ensuring pH homeostasis and defense against toxic chemicals. Various potassium transporter systems, sodium/proton antiporters, and two copies of proton-translocating F1F0-type ATP synthase genes were identified, which might participate in the key pH homeostasis mechanisms in KS32. In addition, the V-type ATP synthase and urea assimilation genes might be used for pH homeostasis in KS41. Genes involved in the modification of membranes by incorporation of cyclopropane fatty acids and hopanoid lipids might be used for reducing proton influx into cells. The two methanotroph genomes possess genes for elaborate heavy metal efflux pumping systems, possibly owing to increased heavy metal toxicity in acidic conditions. Phylogenies of key genes involved in acid adaptation, methane oxidation, and antiviral defense in KS41 were incongruent with that of 16S rRNA. Thus, the detailed analysis of the genome sequences provides new insights into the ecology of methanotrophs responding to soil acidification.
Collapse
Affiliation(s)
- Ngoc-Loi Nguyen
- Department of Microbiology, Chungbuk National University, Cheongju, South Korea
| | - Woon-Jong Yu
- Department of Microbiology, Chungbuk National University, Cheongju, South Korea
| | - Joo-Han Gwak
- Department of Microbiology, Chungbuk National University, Cheongju, South Korea
| | - So-Jeong Kim
- Geologic Environment Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, South Korea
| | - Soo-Je Park
- Department of Biology, Jeju National University, Jeju City, South Korea
| | - Craig W Herbold
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Jong-Geol Kim
- Department of Microbiology, Chungbuk National University, Cheongju, South Korea
| | - Man-Young Jung
- Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Sung-Keun Rhee
- Department of Microbiology, Chungbuk National University, Cheongju, South Korea
| |
Collapse
|
33
|
Modin O. A mathematical model of aerobic methane oxidation coupled to denitrification. ENVIRONMENTAL TECHNOLOGY 2018; 39:1217-1225. [PMID: 28443363 DOI: 10.1080/09593330.2017.1323961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/21/2017] [Indexed: 06/07/2023]
Abstract
Aerobic methanotrophic bacteria use methane as their only source of energy and carbon. They release organic compounds that can serve as electron donors for co-existing denitrifiers. This interaction between methanotrophs and denitrifiers is known to contribute to nitrogen losses in natural environments and has also been exploited by researchers for denitrification of nitrate-contaminated wastewater. The purpose of this study was to develop a mathematical model describing aerobic methane oxidation coupled to denitrification in suspended-growth reactors. The model considered the activities of three microbial groups: aerobic methanotrophs, facultative methylotrophs, and facultative heterotrophs. The model was tested against data from the scientific literature and used to explore the effects of the oxygen mass transfer coefficient, the solids retention time, and the fraction methane in the feed gas on nitrate removal. The fraction of methane in the feed gas was found to be critical for the nitrate removal rate. A value of about 15% in air was optimal. A lower methane fraction led to excess oxygen, which was detrimental for denitrification. A higher fraction led to oxygen-limitation, which restricted the growth rate of methanotrophs in the reactor.
Collapse
Affiliation(s)
- Oskar Modin
- a Division of Water Environment Technology, Department of Architecture and Civil Engineering , Chalmers University of Technology , Gothenburg , Sweden
| |
Collapse
|
34
|
Methane stimulates massive nitrogen loss from freshwater reservoirs in India. Nat Commun 2018; 9:1265. [PMID: 29593290 PMCID: PMC5871758 DOI: 10.1038/s41467-018-03607-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/28/2018] [Indexed: 11/08/2022] Open
Abstract
The fate of the enormous amount of reactive nitrogen released to the environment by human activities in India is unknown. Here we show occurrence of seasonal stratification and generally low concentrations of dissolved inorganic combined nitrogen, and high molecular nitrogen (N2) to argon ratio, thus suggesting seasonal loss to N2 in anoxic hypolimnia of several dam-reservoirs. However, 15N-experiments yielded low rates of denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium-except in the presence of methane (CH4) that caused ~12-fold increase in denitrification. While nitrite-dependent anaerobic methanotrophs belonging to the NC10 phylum were present, previously considered aerobic methanotrophs were far more abundant (up to 13.9%) in anoxic hypolimnion. Methane accumulation in anoxic freshwater systems seems to facilitate rapid loss of reactive nitrogen, with generally low production of nitrous oxide (N2O), through widespread coupling between methanotrophy and denitrification, potentially mitigating eutrophication and emissions of CH4 and N2O to the atmosphere.
Collapse
|
35
|
Molybdenum-Based Diazotrophy in a Sphagnum Peatland in Northern Minnesota. Appl Environ Microbiol 2017; 83:AEM.01174-17. [PMID: 28667112 DOI: 10.1128/aem.01174-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 06/28/2017] [Indexed: 11/20/2022] Open
Abstract
Microbial N2 fixation (diazotrophy) represents an important nitrogen source to oligotrophic peatland ecosystems, which are important sinks for atmospheric CO2 and are susceptible to the changing climate. The objectives of this study were (i) to determine the active microbial group and type of nitrogenase mediating diazotrophy in an ombrotrophic Sphagnum-dominated peat bog (the S1 peat bog, Marcell Experimental Forest, Minnesota, USA); and (ii) to determine the effect of environmental parameters (light, O2, CO2, and CH4) on potential rates of diazotrophy measured by acetylene (C2H2) reduction and 15N2 incorporation. A molecular analysis of metabolically active microbial communities suggested that diazotrophy in surface peat was primarily mediated by Alphaproteobacteria (Bradyrhizobiaceae and Beijerinckiaceae). Despite higher concentrations of dissolved vanadium ([V] 11 nM) than molybdenum ([Mo] 3 nM) in surface peat, a combination of metagenomic, amplicon sequencing, and activity measurements indicated that Mo-containing nitrogenases dominate over the V-containing form. Acetylene reduction was only detected in surface peat exposed to light, with the highest rates observed in peat collected from hollows with the highest water contents. Incorporation of 15N2 was suppressed 90% by O2 and 55% by C2H2 and was unaffected by CH4 and CO2 amendments. These results suggest that peatland diazotrophy is mediated by a combination of C2H2-sensitive and C2H2-insensitive microbes that are more active at low concentrations of O2 and show similar activity at high and low concentrations of CH4 IMPORTANCE Previous studies indicate that diazotrophy provides an important nitrogen source and is linked to methanotrophy in Sphagnum-dominated peatlands. However, the environmental controls and enzymatic pathways of peatland diazotrophy, as well as the metabolically active microbial populations that catalyze this process, remain in question. Our findings indicate that oxygen levels and photosynthetic activity override low nutrient availability in limiting diazotrophy and that members of the Alphaproteobacteria (Rhizobiales) catalyze this process at the bog surface using the molybdenum-based form of the nitrogenase enzyme.
Collapse
|
36
|
Zhang Y, Chen JX, Wen LL, Tang Y, Zhao HP. Effects of salinity on simultaneous reduction of perchlorate and nitrate in a methane-based membrane biofilm reactor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:24248-24255. [PMID: 27646453 DOI: 10.1007/s11356-016-7678-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 09/12/2016] [Indexed: 06/06/2023]
Abstract
This study builds upon prior work showing that methane (CH4) could be utilized as the sole electron donor and carbon source in a membrane biofilm reactor (MBfR) for complete perchlorate (ClO4-) and nitrate (NO3-) removal. Here, we further investigated the effects of salinity on the simultaneous removal of the two contaminants in the reactor. By testing ClO4- and NO3- at different salinities, we found that the reactor performance was very sensitive to salinity. While 0.2 % salinity did not significantly affect the hydrogen-based MBfR for ClO4- and NO3- removals, 1 % salinity completely inhibited ClO4- reduction and significantly lowered NO3- reduction in the CH4-based MBfR. In salinity-free conditions, NO3- and ClO4- removal fluxes were 0.171 g N/m2-day and 0.091 g/m2-day, respectively, but NO3- removal fluxes dropped to 0.0085 g N/m2-day and ClO4- reduction was completely inhibited when the medium changed to 1 % salinity. Scanning electron microscopy (SEM) showed that the salinity dramatically changed the microbial morphology, which led to the development of wire-like cell structures. Quantitative real-time PCR (qPCR) indicated that the total number of microorganisms and abundances of functional genes significantly declined in the presence of NaCl. The relative abundances of Methylomonas (methanogens) decreased from 31.3 to 5.9 % and Denitratisoma (denitrifiers) decreased from 10.6 to 4.4 % when 1 % salinity was introduced.
Collapse
Affiliation(s)
- Yin Zhang
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China
- Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jia-Xian Chen
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China
- Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China
| | - Li-Lian Wen
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China
- Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China
| | - Youneng Tang
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310-6046, USA
| | - He-Ping Zhao
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China.
- Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China.
| |
Collapse
|
37
|
Walkiewicz A, Bulak P, Brzezińska M, Wnuk E, Bieganowski A. Methane oxidation in heavy metal contaminated Mollic Gleysol under oxic and hypoxic conditions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 213:403-411. [PMID: 26946175 DOI: 10.1016/j.envpol.2016.02.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 05/26/2023]
Abstract
Soils are the largest terrestrial sink for methane (CH4). However, heavy metals may exert toxicity to soil microorganisms, including methanotrophic bacteria. We tested the effect of lead (Pb), zinc (Zn) and nickel (Ni) on CH4 oxidation (1% v/v) and dehydrogenase activity, an index of the activity of the total soil microbial community in Mollic Gleysol soil in oxic and hypoxic conditions (oxia and hypoxia, 20% and 10% v/v O2, respectively). Metals were added in doses corresponding to the amounts permitted of Pb, Zn, Ni in agricultural soils (60, 120, 35 mg kg(-1), respectively), and half and double of these doses. Relatively low metal contents and O2 status reflect the conditions of most agricultural soils of temperate regions. Methane consumption showed high tolerance to heavy metals. The effect of O2 status was stronger than that of metals. CH4 consumption was enhanced under hypoxia, where both the start and the completion of the control and contaminated treatment were faster than under oxic conditions. Dehydrogenase activity, showed higher sensitivity to the contamination (except for low Ni dose), with a stronger effect of heavy metals, than that of the O2 status.
Collapse
Affiliation(s)
- A Walkiewicz
- Institute of Agrophysics, Polish Academy of Sciences, Department of Natural Environment Biogeochemistry, Doświadczalna 4, 20-290, Lublin, Poland.
| | - P Bulak
- Institute of Agrophysics, Polish Academy of Sciences, Department of Natural Environment Biogeochemistry, Doświadczalna 4, 20-290, Lublin, Poland
| | - M Brzezińska
- Institute of Agrophysics, Polish Academy of Sciences, Department of Natural Environment Biogeochemistry, Doświadczalna 4, 20-290, Lublin, Poland
| | - E Wnuk
- Institute of Agrophysics, Polish Academy of Sciences, Department of Natural Environment Biogeochemistry, Doświadczalna 4, 20-290, Lublin, Poland
| | - A Bieganowski
- Institute of Agrophysics, Polish Academy of Sciences, Department of Natural Environment Biogeochemistry, Doświadczalna 4, 20-290, Lublin, Poland
| |
Collapse
|
38
|
Chen R, Luo YH, Chen JX, Zhang Y, Wen LL, Shi LD, Tang Y, Rittmann BE, Zheng P, Zhao HP. Evolution of the microbial community of the biofilm in a methane-based membrane biofilm reactor reducing multiple electron acceptors. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:9540-9548. [PMID: 26841777 DOI: 10.1007/s11356-016-6146-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 01/20/2016] [Indexed: 06/05/2023]
Abstract
Previous work documented complete perchlorate reduction in a membrane biofilm reactor (MBfR) using methane as the sole electron donor and carbon source. This work explores how the biofilm's microbial community evolved as the biofilm stage-wise reduced different combinations of perchlorate, nitrate, and nitrite. The initial inoculum, carrying out anaerobic methane oxidation coupled to denitrification (ANMO-D), was dominated by uncultured Anaerolineaceae and Ferruginibacter sp. The microbial community significantly changed after it was inoculated into the CH4-based MBfR and fed with a medium containing perchlorate and nitrite. Archaea were lost within the first 40 days, and the uncultured Anaerolineaceae and Ferruginibacter sp. also had significant losses. Replacing them were anoxic methanotrophs, especially Methylocystis, which accounted for more than 25 % of total bacteria. Once the methanotrophs became important, methanol-oxidizing denitrifying bacteria, namely, Methloversatilis and Methylophilus, became important in the biofilm, probably by utilizing organic matter generated by the metabolism of methanotrophs. When methane consumption was equal to the maximum-possible electron-donor supply, Methylomonas, also an anoxic methanotroph, accounted for >10 % of total bacteria and remained a major part of the community until the end of the experiments. We propose that aerobic methane oxidation coupled to denitrification and perchlorate reduction (AMO-D and AMO-PR) directly oxidized methane and reduced NO3 (-) to NO2 (-) or N2O under anoxic condition, producing organic matter for methanol-assimilating denitrification and perchlorate reduction (MA-D and MA-PR) to reduce NO3 (-). Simultaneously, bacteria capable of anaerobic methane oxidation coupled to denitrification and perchlorate reduction (ANMO-D and ANMO-PR) used methane as the electron donor to respire NO3 (-) or ClO4 (-) directly. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Ran Chen
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yi-Hao Luo
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jia-Xian Chen
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yin Zhang
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China
| | - Li-Lian Wen
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, Zhejiang University, Hangzhou, China
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China
| | - Ling-Dong Shi
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China
| | - Youneng Tang
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310-6046, USA
| | - Bruce E Rittmann
- Swette Center for Environmental Biotechnology, Biodesign Institute at Arizona State University, P.O. Box 875701, Tempe, AZ, 85287-5701, USA
| | - Ping Zheng
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, Zhejiang University, Hangzhou, China
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China
| | - He-Ping Zhao
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Zhejiang University, Hangzhou, Zhejiang, China.
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, Zhejiang University, Hangzhou, China.
- Department of Environmental Engineering, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China.
| |
Collapse
|
39
|
Kits KD, Campbell DJ, Rosana AR, Stein LY. Diverse electron sources support denitrification under hypoxia in the obligate methanotroph Methylomicrobium album strain BG8. Front Microbiol 2015; 6:1072. [PMID: 26500622 PMCID: PMC4594100 DOI: 10.3389/fmicb.2015.01072] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/18/2015] [Indexed: 11/30/2022] Open
Abstract
Aerobic methane-oxidizing bacteria (MOB) are a diverse group of microorganisms that are ubiquitous in natural environments. Along with anaerobic MOB and archaea, aerobic methanotrophs are critical for attenuating emission of methane to the atmosphere. Clearly, nitrogen availability in the form of ammonium and nitrite have strong effects on methanotrophic activity and their natural community structures. Previous findings show that nitrite amendment inhibits the activity of some cultivated methanotrophs; however, the physiological pathways that allow some strains to transform nitrite, expression of gene inventories, as well as the electron sources that support this activity remain largely uncharacterized. Here we show that Methylomicrobium album strain BG8 utilizes methane, methanol, formaldehyde, formate, ethane, ethanol, and ammonia to support denitrification activity under hypoxia only in the presence of nitrite. We also demonstrate that transcript abundance of putative denitrification genes, nirS and one of two norB genes, increased in response to nitrite. Furthermore, we found that transcript abundance of pxmA, encoding the alpha subunit of a putative copper-containing monooxygenase, increased in response to both nitrite and hypoxia. Our results suggest that expression of denitrification genes, found widely within genomes of aerobic methanotrophs, allow the coupling of substrate oxidation to the reduction of nitrogen oxide terminal electron acceptors under oxygen limitation. The present study expands current knowledge of the metabolic flexibility of methanotrophs by revealing that a diverse array of electron donors support nitrite reduction to nitrous oxide under hypoxia.
Collapse
Affiliation(s)
- K Dimitri Kits
- Department of Biological Sciences, Faculty of Science, University of Alberta Edmonton, AB, Canada
| | - Dustin J Campbell
- Department of Biological Sciences, Faculty of Science, University of Alberta Edmonton, AB, Canada
| | - Albert R Rosana
- Department of Biological Sciences, Faculty of Science, University of Alberta Edmonton, AB, Canada
| | - Lisa Y Stein
- Department of Biological Sciences, Faculty of Science, University of Alberta Edmonton, AB, Canada
| |
Collapse
|
40
|
Myung J, Wang Z, Yuan T, Zhang P, Van Nostrand JD, Zhou J, Criddle CS. Production of Nitrous Oxide from Nitrite in Stable Type II Methanotrophic Enrichments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:10969-10975. [PMID: 26301949 DOI: 10.1021/acs.est.5b03385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The coupled aerobic-anoxic nitrous decomposition operation is a new process for wastewater treatment that removes nitrogen from wastewater and recovers energy from the nitrogen in three steps: (1) NH4(+) oxidation to NO2(-), (2) NO2(-) reduction to N2O, and (3) N2O conversion to N2 with energy production. Here, we demonstrate that type II methanotrophic enrichments can mediate step two by coupling oxidation of poly(3-hydroxybutyrate) (P3HB) to NO2(-) reduction. Enrichments grown with NH4(+) and NO2(-) were subject to alternating 48-h aerobic and anoxic periods, in which CH4 and NO2(-) were added together in a "coupled" mode of operation or separately in a "decoupled mode". Community structure was stable in both modes and dominated by Methylocystis. In the coupled mode, production of P3HB and N2O was low. In the decoupled mode, significant P3HB was produced, and oxidation of P3HB drove reduction of NO2(-) to N2O with ∼ 70% conversion for >30 cycles (120 d). In batch tests of wasted cells from the decoupled mode, N2O production rates increased at low O2 or high NO2(-) levels. The results are significant for the development of engineered processes that remove nitrogen from wastewater and for understanding of conditions that favor environmental production of N2O.
Collapse
Affiliation(s)
- Jaewook Myung
- Department of Civil and Environmental Engineering, Stanford University , Stanford, California 94305, United States
| | - Zhiyue Wang
- Department of Civil and Environmental Engineering, Stanford University , Stanford, California 94305, United States
| | - Tong Yuan
- Institute for Environmental Genomics, Department of Microbiology and Plant Science, University of Oklahoma , Norman, Oklahoma 73019, United States
| | - Ping Zhang
- Institute for Environmental Genomics, Department of Microbiology and Plant Science, University of Oklahoma , Norman, Oklahoma 73019, United States
| | - Joy D Van Nostrand
- Institute for Environmental Genomics, Department of Microbiology and Plant Science, University of Oklahoma , Norman, Oklahoma 73019, United States
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Science, University of Oklahoma , Norman, Oklahoma 73019, United States
| | - Craig S Criddle
- Department of Civil and Environmental Engineering, Stanford University , Stanford, California 94305, United States
- Woods Institute for the Environment, Stanford, California 94305, United States
- William and Cloy Codiga Resource Recovery Center, Stanford, California 94305, United States
| |
Collapse
|
41
|
Kits KD, Klotz MG, Stein LY. Methane oxidation coupled to nitrate reduction under hypoxia by the Gammaproteobacterium Methylomonas denitrificans, sp. nov. type strain FJG1. Environ Microbiol 2015; 17:3219-32. [PMID: 25580993 DOI: 10.1111/1462-2920.12772] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 12/31/2014] [Indexed: 02/02/2023]
Abstract
Obligate methanotrophs belonging to the Phyla Proteobacteria and Verrucomicrobia require oxygen for respiration and methane oxidation; nevertheless, aerobic methanotrophs are abundant and active in low oxygen environments. While genomes of some aerobic methanotrophs encode putative nitrogen oxide reductases, it is not understood whether these metabolic modules are used for NOx detoxification, denitrification or other purposes. Here we demonstrate using microsensor measurements that a gammaproteobacterial methanotroph Methylomonas denitrificans sp. nov. strain FJG1(T) couples methane oxidation to nitrate reduction under oxygen limitation, releasing nitrous oxide as a terminal product. Illumina RNA-Seq data revealed differential expression of genes encoding a denitrification pathway previously unknown to methanotrophs as well as the pxmABC operon in M. denitrificans sp. nov. strain FJG1(T) in response to hypoxia. Physiological and transcriptome data indicate that genetic inventory encoding the denitrification pathway is upregulated only upon availability of nitrate under oxygen limitation. In addition, quantitation of ATP levels demonstrates that the denitrification pathway employs inventory such as nitrate reductase NarGH serving M. denitrificans sp. nov. strain FJG1(T) to conserve energy during oxygen limitation. This study unravelled an unexpected metabolic flexibility of aerobic methanotrophs, thereby assigning these bacteria a new role at the metabolic intersection of the carbon and nitrogen cycles.
Collapse
Affiliation(s)
- K Dimitri Kits
- Department of Biological Sciences, University of Alberta, CW405, Biological Sciences Building, Edmonton, AB, T6G 2E9, Canada
| | - Martin G Klotz
- Department of Biological Sciences, University of North Carolina, 9201 University City Boulevard, Charlotte, NC, 28223, USA.,Institute of Marine Microbes and Ecospheres and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
| | - Lisa Y Stein
- Department of Biological Sciences, University of Alberta, CW405, Biological Sciences Building, Edmonton, AB, T6G 2E9, Canada
| |
Collapse
|
42
|
Frutos OD, Arvelo IA, Pérez R, Quijano G, Muñoz R. Continuous nitrous oxide abatement in a novel denitrifying off-gas bioscrubber. Appl Microbiol Biotechnol 2014; 99:3695-706. [DOI: 10.1007/s00253-014-6329-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/11/2014] [Accepted: 12/14/2014] [Indexed: 01/13/2023]
|
43
|
Dam B, Dam S, Kim Y, Liesack W. Ammonium induces differential expression of methane and nitrogen metabolism-related genes in Methylocystis sp. strain SC2. Environ Microbiol 2014; 16:3115-27. [PMID: 24373058 DOI: 10.1111/1462-2920.12367] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 12/14/2013] [Indexed: 11/30/2022]
Abstract
Nitrogen source and concentration are major determinants of methanotrophic activity, but their effect on global gene expression is poorly studied. Methylocystis sp. strain SC2 produces two isozymes of particulate methane monooxygenase. These are encoded by pmoCAB1 (low-affinity pMMO1) and pmoCAB2 (high-affinity pMMO2). We used RNA-Seq to identify strain SC2 genes that respond to standard (10 mM) and high (30 mM) NH4(+) concentrations in the medium, compared with 10 mM NO3(-). While the expression of pmoCAB1 was unaffected, pmoCAB2 was significantly downregulated (log2 fold changes of -5.0 to -6.0). Among nitrogen metabolism-related processes, genes involved in hydroxylamine detoxification (haoAB) were highly upregulated, while those for assimilatory nitrate/nitrite reduction, high-affinity ammonium uptake and nitrogen regulatory protein PII were downregulated. Differential expression of pmoCAB2 and haoAB was independently validated by end-point reverse transcription polymerase chain reaction. Methane oxidation by SC2 cells exposed to 30 mM NH4(+) was inhibited at ≤ 400 ppmv CH4 , where pMMO2 but not pMMO1 is functional. When transferred back to standard nitrogen concentration, methane oxidation capability and pmoCAB2 expression were restored. Given that Methylocystis contributes to atmospheric methane oxidation in upland soils, differential expression of pmoCAB2 explains, at least to some extent, the strong inhibitory effect of ammonium fertilizers on this activity.
Collapse
Affiliation(s)
- Bomba Dam
- Max Planck Institute for Terrestrial Microbiology, D-35043, Marburg, Germany; Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, D-35043, Marburg, Germany
| | | | | | | |
Collapse
|