101
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Kroeger ME, Meredith LK, Meyer KM, Webster KD, de Camargo PB, de Souza LF, Tsai SM, van Haren J, Saleska S, Bohannan BJM, Rodrigues JLM, Berenguer E, Barlow J, Nüsslein K. Rainforest-to-pasture conversion stimulates soil methanogenesis across the Brazilian Amazon. THE ISME JOURNAL 2021; 15:658-672. [PMID: 33082572 PMCID: PMC8027882 DOI: 10.1038/s41396-020-00804-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 09/03/2020] [Accepted: 10/02/2020] [Indexed: 01/30/2023]
Abstract
The Amazon rainforest is a biodiversity hotspot and large terrestrial carbon sink threatened by agricultural conversion. Rainforest-to-pasture conversion stimulates the release of methane, a potent greenhouse gas. The biotic methane cycle is driven by microorganisms; therefore, this study focused on active methane-cycling microorganisms and their functions across land-use types. We collected intact soil cores from three land use types (primary rainforest, pasture, and secondary rainforest) of two geographically distinct areas of the Brazilian Amazon (Santarém, Pará and Ariquemes, Rondônia) and performed DNA stable-isotope probing coupled with metagenomics to identify the active methanotrophs and methanogens. At both locations, we observed a significant change in the composition of the isotope-labeled methane-cycling microbial community across land use types, specifically an increase in the abundance and diversity of active methanogens in pastures. We conclude that a significant increase in the abundance and activity of methanogens in pasture soils could drive increased soil methane emissions. Furthermore, we found that secondary rainforests had decreased methanogenic activity similar to primary rainforests, and thus a potential to recover as methane sinks, making it conceivable for forest restoration to offset greenhouse gas emissions in the tropics. These findings are critical for informing land management practices and global tropical rainforest conservation.
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Affiliation(s)
- Marie E. Kroeger
- grid.266683.f0000 0001 2184 9220Department of Microbiology, University of Massachusetts Amherst, Amherst, MA USA ,grid.148313.c0000 0004 0428 3079Present Address: Bioenergy and Biome Sciences, Los Alamos National Laboratory, Los Alamos, NM USA
| | - Laura K. Meredith
- grid.134563.60000 0001 2168 186XSchool of Natural Resources and the Environment, University of Arizona, Tucson, AZ USA ,grid.134563.60000 0001 2168 186XBiosphere 2, University of Arizona, Tucson, AZ USA
| | - Kyle M. Meyer
- grid.170202.60000 0004 1936 8008Institute of Ecology and Evolution, University of Oregon, Eugene, OR USA ,grid.47840.3f0000 0001 2181 7878Department of Integrative Biology, University of California–Berkeley, Berkeley, CA USA
| | - Kevin D. Webster
- grid.423138.f0000 0004 0637 3991Planetary Science Institute, Tucson, AZ USA
| | - Plinio Barbosa de Camargo
- grid.11899.380000 0004 1937 0722Center for Nuclear Energy in Agriculture, University of São Paulo, São Paulo, SP Brazil
| | - Leandro Fonseca de Souza
- grid.11899.380000 0004 1937 0722Center for Nuclear Energy in Agriculture, University of São Paulo, São Paulo, SP Brazil
| | - Siu Mui Tsai
- grid.11899.380000 0004 1937 0722Center for Nuclear Energy in Agriculture, University of São Paulo, São Paulo, SP Brazil
| | - Joost van Haren
- grid.134563.60000 0001 2168 186XBiosphere 2, University of Arizona, Tucson, AZ USA ,grid.134563.60000 0001 2168 186XHonors College, University of Arizona, Tucson, AZ USA
| | - Scott Saleska
- grid.134563.60000 0001 2168 186XDepartment of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ USA
| | - Brendan J. M. Bohannan
- grid.170202.60000 0004 1936 8008Institute of Ecology and Evolution, University of Oregon, Eugene, OR USA
| | - Jorge L. Mazza Rodrigues
- grid.27860.3b0000 0004 1936 9684Department of Land, Air and Water Resources, University of California, Davis, CA USA
| | - Erika Berenguer
- grid.9835.70000 0000 8190 6402Lancaster Environment Centre, Lancaster University, Lancaster, UK ,grid.4991.50000 0004 1936 8948Environmental Change Institute, University of Oxford, Oxford, UK
| | - Jos Barlow
- grid.9835.70000 0000 8190 6402Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Klaus Nüsslein
- grid.266683.f0000 0001 2184 9220Department of Microbiology, University of Massachusetts Amherst, Amherst, MA USA
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102
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Sharma P, Tripathi S, Chandra R. Metagenomic analysis for profiling of microbial communities and tolerance in metal-polluted pulp and paper industry wastewater. BIORESOURCE TECHNOLOGY 2021; 324:124681. [PMID: 33454444 DOI: 10.1016/j.biortech.2021.124681] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/02/2021] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
This work aimed to study the profiling and efficiency of microbial communities and their abundance in the pulp and paper industry wastewater, which contained toxic metals, high biological oxygen demands, chemical oxygen demand, and ions contents. Sequence alignment of the 16S rRNA V3-V4 variable region zone with the Illumina MiSeq framework revealed 25356 operating taxonomical units (OTUs) derived from the wastewater sample. The major phyla identified in wastewater were Proteobacteria, Bacteroidetes, Firmicutes, Chloroflexi, Actinobacteria, Spirochetes, Patesibacteria, Acidobacteria, and others including unknown microbes. The study showed the function of microbial communities essential for the oxidation and detoxifying of complex contaminants and design of effective remediation techniques for the re-use of polluted wastewater. Findings demonstrated that the ability of different classes of microbes to adapt and survive in metal-polluted wastewater irrespective of their relative distribution, as well as further attention can be provided to its use in the bioremediation process.
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Affiliation(s)
- Pooja Sharma
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University (A Central University), Lucknow 226 025, Uttar Pradesh, India
| | - Sonam Tripathi
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University (A Central University), Lucknow 226 025, Uttar Pradesh, India
| | - Ram Chandra
- Department of Environmental Microbiology, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University (A Central University), Lucknow 226 025, Uttar Pradesh, India.
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103
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Microbial Communities in Methane Cycle: Modern Molecular Methods Gain Insights into Their Global Ecology. ENVIRONMENTS 2021. [DOI: 10.3390/environments8020016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The role of methane as a greenhouse gas in the concept of global climate changes is well known. Methanogens and methanotrophs are two microbial groups which contribute to the biogeochemical methane cycle in soil, so that the total emission of CH4 is the balance between its production and oxidation by microbial communities. Traditional identification techniques, such as selective enrichment and pure-culture isolation, have been used for a long time to study diversity of methanogens and methanotrophs. However, these techniques are characterized by significant limitations, since only a relatively small fraction of the microbial community could be cultured. Modern molecular methods for quantitative analysis of the microbial community such as real-time PCR (Polymerase chain reaction), DNA fingerprints and methods based on high-throughput sequencing together with different “omics” techniques overcome the limitations imposed by culture-dependent approaches and provide new insights into the diversity and ecology of microbial communities in the methane cycle. Here, we review available knowledge concerning the abundances, composition, and activity of methanogenic and methanotrophic communities in a wide range of natural and anthropogenic environments. We suggest that incorporation of microbial data could fill the existing microbiological gaps in methane flux modeling, and significantly increase the predictive power of models for different environments.
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104
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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: 25] [Impact Index Per Article: 8.3] [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.
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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.
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105
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Tikhomirova TS, But SY. Laboratory scale bioreactor designs in the processes of methane bioconversion: Mini-review. Biotechnol Adv 2021; 47:107709. [PMID: 33548452 DOI: 10.1016/j.biotechadv.2021.107709] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 02/07/2023]
Abstract
Global methane emissions have been steadily increasing over the past few decades, exerting a negative effect on the environment. Biogas from landfills and sewage treatment plants is the main anthropogenic source of methane. This makes methane bioconversion one of the priority areas of biotechnology. This process involves the production of biochemical compounds from non-food sources through microbiological synthesis. Methanotrophic bacteria are a promising tool for methane bioconversion due to their ability to use this greenhouse gas and to produce protein-rich biomass, as well as a broad range of useful organic compounds. Currently, methane is used not only to produce biomass and chemical compounds, but also to increase the efficiency of water and solid waste treatment. However, the use of gaseous substrates in biotechnological processes is associated with some difficulties. The low solubility of methane in water is one of the major problems. Different approaches have been involved to encounter these challenges, including different bioreactor and gas distribution designs, solid carriers and bulk sorbents, as well as varying air/oxygen supply, the ratio of volumetric flow rate of gas mixture to its consumption rate, etc. The aim of this review was to summarize the current data on different bioreactor designs and the aspects of their applications for methane bioconversion and wastewater treatment. The bioreactors used in these processes must meet a number of requirements such as low methane emission, improved gas exchange surface, and controlled substrate supply to the reaction zone.
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Affiliation(s)
- Tatyana S Tikhomirova
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», Institutskaya 7, Pushchino, Moscow Region 142290, Russia.
| | - Sergey Y But
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of Sciences, Federal Research Center «Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences», Prospect Nauki 5, Pushchino, Moscow Region 142290, Russia
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106
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Schmitz RA, Peeters SH, Versantvoort W, Picone N, Pol A, Jetten MSM, Op den Camp HJM. Verrucomicrobial methanotrophs: ecophysiology of metabolically versatile acidophiles. FEMS Microbiol Rev 2021; 45:6125968. [PMID: 33524112 PMCID: PMC8498564 DOI: 10.1093/femsre/fuab007] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Methanotrophs are an important group of microorganisms that counteract methane emissions to the atmosphere. Methane-oxidising bacteria of the Alpha- and Gammaproteobacteria have been studied for over a century, while methanotrophs of the phylum Verrucomicrobia are a more recent discovery. Verrucomicrobial methanotrophs are extremophiles that live in very acidic geothermal ecosystems. Currently, more than a dozen strains have been isolated, belonging to the genera Methylacidiphilum and Methylacidimicrobium. Initially, these methanotrophs were thought to be metabolically confined. However, genomic analyses and physiological and biochemical experiments over the past years revealed that verrucomicrobial methanotrophs, as well as proteobacterial methanotrophs, are much more metabolically versatile than previously assumed. Several inorganic gases and other molecules present in acidic geothermal ecosystems can be utilised, such as methane, hydrogen gas, carbon dioxide, ammonium, nitrogen gas and perhaps also hydrogen sulfide. Verrucomicrobial methanotrophs could therefore represent key players in multiple volcanic nutrient cycles and in the mitigation of greenhouse gas emissions from geothermal ecosystems. Here, we summarise the current knowledge on verrucomicrobial methanotrophs with respect to their metabolic versatility and discuss the factors that determine their diversity in their natural environment. In addition, key metabolic, morphological and ecological characteristics of verrucomicrobial and proteobacterial methanotrophs are reviewed.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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107
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Li C, Quan Q, Gan Y, Dong J, Fang J, Wang L, Liu J. Effects of heavy metals on microbial communities in sediments and establishment of bioindicators based on microbial taxa and function for environmental monitoring and management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 749:141555. [PMID: 32841857 DOI: 10.1016/j.scitotenv.2020.141555] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/19/2020] [Accepted: 08/05/2020] [Indexed: 05/20/2023]
Abstract
Heavy metals have always been a research hotspot due to their persistence, hazard and bioaccumulation. Microorganisms are highly sensitive to heavy metal pollution and play an important role in the material cycling and energy flow of the ecosystem. In order to further explore the influence of heavy metals on the diversity, composition, and function of microbial communities in the wetland sediment ecosystem, and to find suitable indicators to reflect heavy metal pollution status, we collected sediments from Huangjinxia nature reserve and determined the physicochemical properties, heavy metal (Cu, Cr, Ni, Pb, Zn, and Mn) concentrations, and microbial information. We found that: the contamination status of the study area stood at a moderate level evaluated by the pollution load index (PLI); heavy metals explained more of microbial community variation than the sediment physicochemical properties; in particular, Cr and Mn negatively affected microbial α-diversity; heavy metals significantly affected the structure of microbial communities, elements Cr, Pb, and Zn showed uniformly negative associations with the relative abundance of bacteria Nitrospirae (including class Nitrospira and order Nitrospirales), Bacteroidetes (including class Bacteroidia), and Verrucomicrobia; moreover, heavy metals affected predicted functions of microbial communities, including metabolic functions, genetic information processes, and functions related to the carbon cycle and the nitrogen cycle. Based on the relative abundance of sensitive microbial taxa and predicted functions, bioindicators [Bacteroidia], 1/[Nitrospira], 1/[Nitrification], and 1/[Aerobic nitrite oxidation] were established to reflect and predict the contamination status of heavy metals in sediments. Our in-depth research on the effects of heavy metals on microorganisms and the establishment of bioindicators provide references and new perspectives for environmental monitoring and management.
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Affiliation(s)
- Changchao Li
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Quan Quan
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, China.
| | - Yandong Gan
- School of Life Sciences, Qufu Normal University, Qufu 273165, China
| | - Junyu Dong
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jiaohui Fang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Lifei Wang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jian Liu
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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108
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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.
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109
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Hall JN, Bollini P. Low‐Temperature, Ambient Pressure Oxidation of Methane to Methanol Over Every Tri‐Iron Node in a Metal–Organic Framework Material. Chemistry 2020; 26:16639-16643. [DOI: 10.1002/chem.202003894] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Indexed: 01/15/2023]
Affiliation(s)
- Jacklyn N. Hall
- Chemical & Biomolecular Engineering University of Houston 4722 Calhoun Rd. Houston TX 77004 USA
| | - Praveen Bollini
- Chemical & Biomolecular Engineering University of Houston 4722 Calhoun Rd. Houston TX 77004 USA
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110
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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.
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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
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111
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Guggenheim C, Freimann R, Mayr MJ, Beck K, Wehrli B, Bürgmann H. Environmental and Microbial Interactions Shape Methane-Oxidizing Bacterial Communities in a Stratified Lake. Front Microbiol 2020; 11:579427. [PMID: 33178162 PMCID: PMC7593551 DOI: 10.3389/fmicb.2020.579427] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/04/2020] [Indexed: 11/13/2022] Open
Abstract
In stratified lakes, methane-oxidizing bacteria (MOB) are strongly mitigating methane fluxes to the atmosphere by consuming methane entering the water column from the sediments. MOB communities in lakes are diverse and vertically structured, but their spatio-temporal dynamics along the water column as well as physico-chemical parameters and interactions with other bacterial species that drive the community assembly have so far not been explored in depth. Here, we present a detailed investigation of the MOB and bacterial community composition and a large set of physico-chemical parameters in a shallow, seasonally stratified, and sub-alpine lake. Four highly resolved vertical profiles were sampled in three different years and during various stages of development of the stratified water column. Non-randomly assembled MOB communities were detected in all compartments. We could identify methane and oxygen gradients and physico-chemical parameters like pH, light, available copper and iron, and total dissolved nitrogen as important drivers of the MOB community structure. In addition, MOB were well-integrated into a bacterial-environmental network. Partial redundancy analysis of the relevance network of physico-chemical variables and bacteria explained up to 84% of the MOB abundances. Spatio-temporal MOB community changes were 51% congruent with shifts in the total bacterial community and 22% of variance in MOB abundances could be explained exclusively by the bacterial community composition. Our results show that microbial interactions may play an important role in structuring the MOB community along the depth gradient of stratified lakes.
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Affiliation(s)
- Carole Guggenheim
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland.,Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Remo Freimann
- Department of Biology, Institute of Molecular Health Sciences, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Magdalena J Mayr
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland.,Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Karin Beck
- Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Bernhard Wehrli
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland.,Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Helmut Bürgmann
- Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
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112
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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.
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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
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113
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Semrau JD, DiSpirito AA, Obulisamy PK, Kang-Yun CS. Methanobactin from methanotrophs: genetics, structure, function and potential applications. FEMS Microbiol Lett 2020; 367:5804726. [PMID: 32166327 DOI: 10.1093/femsle/fnaa045] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022] Open
Abstract
Aerobic methane-oxidizing bacteria of the Alphaproteobacteria have been found to express a novel ribosomally synthesized post-translationally modified polypeptide (RiPP) termed methanobactin (MB). The primary function of MB in these microbes appears to be for copper uptake, but MB has been shown to have multiple capabilities, including oxidase, superoxide dismutase and hydrogen peroxide reductase activities, the ability to detoxify mercury species, as well as acting as an antimicrobial agent. Herein, we describe the diversity of known MBs as well as the genetics underlying MB biosynthesis. We further propose based on bioinformatics analyses that some methanotrophs may produce novel forms of MB that have yet to be characterized. We also discuss recent findings documenting that MBs play an important role in controlling copper availability to the broader microbial community, and as a result can strongly affect the activity of microbes that require copper for important enzymatic transformations, e.g. conversion of nitrous oxide to dinitrogen. Finally, we describe procedures for the detection/purification of MB, as well as potential medical and industrial applications of this intriguing RiPP.
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Affiliation(s)
- Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA 50011
| | | | - Christina S Kang-Yun
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
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114
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Meruvu H, Wu H, Jiao Z, Wang L, Fei Q. From nature to nurture: Essence and methods to isolate robust methanotrophic bacteria. Synth Syst Biotechnol 2020; 5:173-178. [PMID: 32637670 PMCID: PMC7327766 DOI: 10.1016/j.synbio.2020.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/03/2020] [Accepted: 06/18/2020] [Indexed: 02/07/2023] Open
Abstract
Methanotrophic bacteria are entities with innate biocatalytic potential to biofilter and oxidize methane into simpler compounds concomitantly conserving energy, which can contribute to copious industrial applications. The future and efficacy of such industrial applications relies upon acquiring and/or securing robust methanotrophs with taxonomic and phenotypic diversity. Despite several dramatic advances, isolation of robust methanotrophs is still a long-way challenging task with several lacunae to be filled in sequentially. Methanotrophs with high tolerance to methane can be isolated and cultivated by mimicking natural environs, and adopting strategies like adaptive metabolic evolution. This review summarizes existent and innovative methods for methanotrophic isolation and purification, and their respective applications. A comprehensive description of new insights shedding light upon how to isolate and concomitantly augment robust methanotrophic metabolism in an orchestrated fashion follows.
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Affiliation(s)
- Haritha Meruvu
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Hui Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Ziyue Jiao
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Liyan Wang
- Luoyang TMAXTREE Biotechnology Co., Ltd., Luoyang, China
| | - Qiang Fei
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
- Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Jiaotong University, Xi'an, China
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115
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Chen LX, Méheust R, Crits-Christoph A, McMahon KD, Nelson TC, Slater GF, Warren LA, Banfield JF. Large freshwater phages with the potential to augment aerobic methane oxidation. Nat Microbiol 2020; 5:1504-1515. [PMID: 32839536 PMCID: PMC7674155 DOI: 10.1038/s41564-020-0779-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/21/2020] [Indexed: 12/31/2022]
Abstract
There is growing evidence that phages with unusually large genomes are common across various microbiomes, but little is known about their genetic inventories or potential ecosystem impacts. In the present study, we reconstructed large phage genomes from freshwater lakes known to contain bacteria that oxidize methane. Of manually curated genomes, 22 (18 are complete), ranging from 159 kilobase (kb) to 527 kb in length, were found to encode the pmoC gene, an enzymatically critical subunit of the particulate methane monooxygenase, the predominant methane oxidation catalyst in nature. The phage-associated PmoC sequences show high similarity to (>90%), and affiliate phylogenetically with, those of coexisting bacterial methanotrophs, including members of Methyloparacoccus, Methylocystis and Methylobacter spp. In addition, pmoC-phage abundance patterns correlate with those of the coexisting bacterial methanotrophs, supporting host-phage relationships. Future work is needed to determine whether phage-associated PmoC has similar functions to additional copies of PmoC encoded in bacterial genomes, thus contributing to growth on methane. Transcriptomics data from Lake Rotsee (Switzerland) showed that some phage-associated pmoC genes were highly expressed in situ and, of interest, that the most rapidly growing methanotroph was infected by three pmoC-phages. Thus, augmentation of bacterial methane oxidation by pmoC-phages during infection could modulate the efflux of this potent greenhouse gas into the environment.
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Affiliation(s)
- Lin-Xing Chen
- Department of Earth and Planetary Sciences, University of California, Berkeley, CA, USA
| | - Raphaël Méheust
- Department of Earth and Planetary Sciences, University of California, Berkeley, CA, USA
| | | | - Katherine D McMahon
- Departments of Civil and Environmental Engineering, and Bacteriology, University of Wisconsin, Madison, WI, USA
| | | | - Gregory F Slater
- School of Geography and Earth Science, McMaster University, Hamilton, Ontario, Canada
| | - Lesley A Warren
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, Ontario, Canada.,School of Geography and Earth Science, McMaster University, Hamilton, Ontario, Canada
| | - Jillian F Banfield
- Department of Earth and Planetary Sciences, University of California, Berkeley, CA, USA. .,Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA. .,Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA. .,Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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116
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Role of Microorganisms in the Remediation of Wastewater in Floating Treatment Wetlands: A Review. SUSTAINABILITY 2020. [DOI: 10.3390/su12145559] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This article provides useful information for understanding the specific role of microbes in the pollutant removal process in floating treatment wetlands (FTWs). The current literature is collected and organized to provide an insight into the specific role of microbes toward plants and pollutants. Several aspects are discussed, such as important components of FTWs, common bacterial species, rhizospheric and endophytes bacteria, and their specific role in the pollutant removal process. The roots of plants release oxygen and exudates, which act as a substrate for microbial growth. The bacteria attach themselves to the roots and form biofilms to get nutrients from the plants. Along the plants, the microbial community also influences the performance of FTWs. The bacterial community contributes to the removal of nitrogen, phosphorus, toxic metals, hydrocarbon, and organic compounds. Plant–microbe interaction breaks down complex compounds into simple nutrients, mobilizes metal ions, and increases the uptake of pollutants by plants. The inoculation of the roots of plants with acclimatized microbes may improve the phytoremediation potential of FTWs. The bacteria also encourage plant growth and the bioavailability of toxic pollutants and can alleviate metal toxicity.
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117
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Kang CS, Dunfield PF, Semrau JD. The origin of aerobic methanotrophy within the Proteobacteria. FEMS Microbiol Lett 2020; 366:5485640. [PMID: 31054238 DOI: 10.1093/femsle/fnz096] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/02/2019] [Indexed: 11/13/2022] Open
Abstract
Aerobic methanotrophs play critical roles in the global carbon cycle, but despite their environmental ubiquity, they are phylogenetically restricted. Via bioinformatic analyses, it is shown that methanotrophy likely arose from methylotrophy from the lateral gene transfer of either of the two known forms of methane monooxygenase (particulate and soluble methane monooxygenases). Moreover, it appears that both known forms of pyrroloquinoline quinone-dependent methanol dehydrogenase (MeDH) found in methanotrophs-the calcium-containing Mxa-MeDH and the rare earth element-containing Xox-MeDH-were likely encoded in the genomes before the acquisition of the methane monooxygenases (MMOs), but that some methanotrophs subsequently received an additional copy of Xox-MeDH-encoding genes via lateral gene transfer. Further, data are presented that indicate the evolution of methanotrophy from methylotrophy not only required lateral transfer of genes encoding for methane monooxygenases, but also likely the pre-existence of a means of collecting copper. Given the emerging interest in valorizing methane via biological platforms, it is recommended that future strategies for heterologous expression of methane monooxygenase for conversion of methane to methanol also include cloning of genes encoding mechanism(s) of copper uptake, especially for expression of particulate methane monooxygenase.
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Affiliation(s)
- Christina S Kang
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
| | - Peter F Dunfield
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI, USA 48109-2125
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118
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Challa S, Smith TJ. Isolation of a methane-oxidizing bacterium that bioremediates hexavalent chromium from a formerly industrialized Suburban River. Lett Appl Microbiol 2020; 71:287-293. [PMID: 32470995 DOI: 10.1111/lam.13330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 01/21/2023]
Abstract
Sediment samples were taken from sediment adjacent to a suburban river in Sheffield in Northern England that had suffered heavy metal pollution due to previous activity of the steel industry (between the 17th and 19th centuries). The most abundant heavy metals found in the samples were lead, chromium, nickel, arsenic and cobalt, with maximum concentrations of 412·80, 25·232, 25·196, 8·123 and 7·66 mg kg-1 , respectively. Enrichment cultures were set up using methane as carbon and energy source, as a result of which a strain of methanotroph was isolated that was shown via 16S rRNA gene sequencing to be a strain Methylomonas koyamae and given the designation SHU1. M. koyamae SHU1 removed hexavalent chromium from an initial concentration of 10 ppm, which was inhibited by the metabolic inhibitor sodium azide or the methane monooxygenase inhibitor phenylacetylene. To the authors' knowledge, this is the first description of a strain of the widely environmentally distributed genus Methylomonas that is capable of remediating hexavalent chromium. SIGNIFICANCE AND IMPACT OF THE STUDY: Aerobic methanotrophic bacteria are known for bioremediation of an increasing range of organic and inorganic pollutants, using methane as carbon and energy source. Previously, one laboratory methanotroph strain, Methylococcus capsulatus Bath, was known to bioremediate toxic chromium (VI) by reducing it to chromium (III). Here, a newly isolated methanotroph strain, Methylomonas koyamae SHU1, has been shown able to remediate chromium (VI). This indicates that chromium (VI) bioremediation is not unique to M. capsulatus and moreover adds weight to the suggestion that methanotrophs may contribute directly to chromium (VI) detoxification in nature and in polymicrobial bioremediation fed with methane.
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Affiliation(s)
- S Challa
- Biomolecular Sciences Research Centre, College of Heath, Wellbeing and Life Sciences, Sheffield Hallam University, Sheffield, UK
| | - T J Smith
- Biomolecular Sciences Research Centre, College of Heath, Wellbeing and Life Sciences, Sheffield Hallam University, Sheffield, UK
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119
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Tian HJ, Feng J, Zhang LM, He JZ, Liu YR. Ecological drivers of methanotrophic communities in paddy soils around mercury mining areas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 721:137760. [PMID: 32169650 DOI: 10.1016/j.scitotenv.2020.137760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/04/2020] [Accepted: 03/04/2020] [Indexed: 06/10/2023]
Abstract
Methanotrophs play a crucial role in mitigating methane (CH4) emission by oxidizing produced CH4 in paddy soils; however, ecological drivers of methanotrophic community in the soils around heavy metal contaminated areas remain unclear. In this study, we evaluated the effects of heavy metal pollution and soil properties on the abundance, diversity and composition of methanotrophic community in paddy soils from two typical mercury (Hg) mining regions in southwest China. The results of random forest and structure equation models suggest that both heavy metal content and soil nutrients greatly influenced the attributes of methanotrophic community. In general, the abundance and diversity of methanotrophs were negatively related to soil Hg content, but showed positive correlation with soil organic carbon content. However, the other metals (cadmium (Cd), nickel (Ni), lead (Pb), arsenic (As), zinc (Zn)) had inconsistent associations with the microbial indexes of methanotrophic community in the soil. Elevated levels of heavy metal and nutrients in the soils shifted the community composition of methanotrophs. For example, Pb, As and Zn contents had negative associations with the relative abundance of Methylocaldum. In addition, changes in the relative abundance of ecological clusters within the co-occurrence network of methanotrophs were related to metal contents and soil properties. Together, our findings provide novel insights into understanding ecological drivers of methanotrophic community in paddy soils around Hg mining regions, with important implications for mitigating CH4 emissions in terrestrial ecosystems.
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Affiliation(s)
- Hua-Jing Tian
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiao Feng
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China.
| | - Li-Mei Zhang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ji-Zheng He
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yu-Rong Liu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China.
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120
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Mahamoud Ahmed A, Tardy V, Bonnineau C, Billard P, Pesce S, Lyautey E. Changes in sediment microbial diversity following chronic copper-exposure induce community copper-tolerance without increasing sensitivity to arsenic. JOURNAL OF HAZARDOUS MATERIALS 2020; 391:122197. [PMID: 32058227 DOI: 10.1016/j.jhazmat.2020.122197] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/22/2020] [Accepted: 01/26/2020] [Indexed: 06/10/2023]
Abstract
Sediment microbial communities were exposed for 21 days to an environmental concentration of copper to assess Cu-induced composition changes and resulting effects on microbial sensitivity to acute Cu and As toxicity. Chronic Cu exposure reduced the diversity of the bacterial and archaeal communities from Day 0 to Day 21. The pollution-induced community tolerance concept (PICT) predicts that loss of the most sensitive taxa and gain of more tolerant ones should increase the capacity of Cu-exposed communities to tolerate acute Cu toxicity. Although diversity loss and functional costs of adaptation could have increased their sensitivity to subsequent toxic stress, no increased sensitivity to As was observed. PICT responses varied according to heterotrophic activity, selected as the functional endpoint for toxicity testing, with different results for Cu and As. This suggests that induced tolerance to Cu and As was supported by different species with different metabolic capacities. Ecological risk assessment of contaminants would gain accuracy from further research on the relative contribution of tolerance acquisition and co-tolerance processes on the functional response of microbial communities.
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Affiliation(s)
- Ayanleh Mahamoud Ahmed
- INRAE, UR RiverLy, 69625 Villeurbanne, France; Univ. Savoie Mont Blanc, INRAE, CARRTEL, 74200 Thonon-les-Bains, France; Centre de Recherche, Université de Djibouti, BP 1904 Djibouti Ville, Djibouti
| | - Vincent Tardy
- INRAE, UR RiverLy, 69625 Villeurbanne, France; Univ. Savoie Mont Blanc, INRAE, CARRTEL, 74200 Thonon-les-Bains, France
| | | | - Patrick Billard
- Université de Lorraine, LIEC, UMR7360, Vandoeuvre-lès-Nancy, 54501, France
| | | | - Emilie Lyautey
- INRAE, UR RiverLy, 69625 Villeurbanne, France; Univ. Savoie Mont Blanc, INRAE, CARRTEL, 74200 Thonon-les-Bains, France.
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121
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Stein LY. The Long-Term Relationship between Microbial Metabolism and Greenhouse Gases. Trends Microbiol 2020; 28:500-511. [DOI: 10.1016/j.tim.2020.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/09/2020] [Accepted: 01/16/2020] [Indexed: 11/26/2022]
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122
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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.
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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.
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123
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Synergistic Effects of a Chalkophore, Methanobactin, on Microbial Methylation of Mercury. Appl Environ Microbiol 2020; 86:AEM.00122-20. [PMID: 32220843 DOI: 10.1128/aem.00122-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/24/2020] [Indexed: 11/20/2022] Open
Abstract
Microbial production of the neurotoxin methylmercury (MeHg) is a significant health and environmental concern, as it can bioaccumulate and biomagnify in the food web. A chalkophore or a copper-binding compound, termed methanobactin (MB), has been shown to form strong complexes with mercury [as Hg(II)] and also enables some methanotrophs to degrade MeHg. It is unknown, however, if Hg(II) binding with MB can also impede Hg(II) methylation by other microbes. Contrary to expectations, MB produced by the methanotroph Methylosinus trichosporium OB3b (OB3b-MB) enhanced the rate and efficiency of Hg(II) methylation more than that observed with thiol compounds (such as cysteine) by the mercury-methylating bacteria Desulfovibrio desulfuricans ND132 and Geobacter sulfurreducens PCA. Compared to no-MB controls, OB3b-MB decreased the rates of Hg(II) sorption and internalization, but increased methylation by 5- to 7-fold, suggesting that Hg(II) complexation with OB3b-MB facilitated exchange and internal transfer of Hg(II) to the HgcAB proteins required for methylation. Conversely, addition of excess amounts of OB3b-MB or a different form of MB from Methylocystis strain SB2 (SB2-MB) inhibited Hg(II) methylation, likely due to greater binding of Hg(II). Collectively, our results underscore the complex roles of microbial exogenous metal-scavenging compounds in controlling net production and bioaccumulation of MeHg in the environment.IMPORTANCE Some anaerobic microorganisms convert inorganic mercury (Hg) into the neurotoxin methylmercury, which can bioaccumulate and biomagnify in the food web. While the genetic basis of microbial mercury methylation is known, factors that control net methylmercury production in the environment are still poorly understood. Here, it is shown that mercury methylation can be substantially enhanced by one form of an exogenous copper-binding compound (methanobactin) produced by some methanotrophs, but not by another. This novel finding illustrates that complex interactions exist between microbes and that these interactions can potentially affect the net production of methylmercury in situ.
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124
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Biderre-Petit C, Taib N, Gardon H, Hochart C, Debroas D. New insights into the pelagic microorganisms involved in the methane cycle in the meromictic Lake Pavin through metagenomics. FEMS Microbiol Ecol 2020; 95:5092586. [PMID: 30203066 DOI: 10.1093/femsec/fiy183] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 09/06/2018] [Indexed: 11/13/2022] Open
Abstract
Advances in metagenomics have given rise to the possibility of obtaining genome sequences from uncultured microorganisms, even for those poorly represented in the microbial community, thereby providing an important means to study their ecology and evolution. In this study, metagenomic sequencing was carried out at four sampling depths having different oxygen concentrations or environmental conditions in the water column of Lake Pavin. By analyzing the sequenced reads and matching the contigs to the proxy genomes of the closest cultivated relatives, we evaluated the metabolic potential of the dominant planktonic species involved in the methane cycle. We demonstrated that methane-producing communities were dominated by the genus Methanoregula while methane-consuming communities were dominated by the genus Methylobacter, thus confirming prior observations. Our work allowed the reconstruction of a draft of their core metabolic pathways. Hydrogenotrophs, the genes required for acetate activation in the methanogen genome, were also detected. Regarding methanotrophy, Methylobacter was present in the same areas as the non-methanotrophic, methylotrophic Methylotenera, which could suggest a relationship between these two groups. Furthermore, the presence of a large gene inventory for nitrogen metabolism (nitrate transport, denitrification, nitrite assimilation and nitrogen fixation, for instance) was detected in the Methylobacter genome.
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Affiliation(s)
- Corinne Biderre-Petit
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Génome et Environnement, F-63000 Clermont-Ferrand, France
| | - Najwa Taib
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Génome et Environnement, F-63000 Clermont-Ferrand, France
| | - Hélène Gardon
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Génome et Environnement, F-63000 Clermont-Ferrand, France
| | - Corentin Hochart
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Génome et Environnement, F-63000 Clermont-Ferrand, France
| | - Didier Debroas
- Université Clermont Auvergne, CNRS, Laboratoire Microorganismes: Génome et Environnement, F-63000 Clermont-Ferrand, France
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125
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In 't Zandt MH, Liebner S, Welte CU. Roles of Thermokarst Lakes in a Warming World. Trends Microbiol 2020; 28:769-779. [PMID: 32362540 DOI: 10.1016/j.tim.2020.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/10/2020] [Accepted: 04/01/2020] [Indexed: 11/27/2022]
Abstract
Permafrost covers a quarter of the northern hemisphere land surface and contains twice the amount of carbon that is currently present in the atmosphere. Future climate change is expected to reduce its near-surface cover by over 90% by the end of the 21st century, leading to thermokarst lake formation. Thermokarst lakes are point sources of carbon dioxide and methane which release long-term carbon stocks into the atmosphere, thereby initiating a positive climate feedback potentially contributing up to a 0.39°C rise of surface air temperatures by 2300. This review describes the potential role of thermokarst lakes in a warming world and the microbial mechanisms that underlie their contributions to the global greenhouse gas budget.
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Affiliation(s)
- Michiel H In 't Zandt
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands; Netherlands Earth System Science Center, Utrecht University, Heidelberglaan 2, 3584 CS, Utrecht, the Netherlands
| | - Susanne Liebner
- GFZ German Research Centre for Geosciences, Section 3.7 Geomicrobiology, Telegrafenberg, 14473 Potsdam, Germany; University of Potsdam, Institute of Biochemistry and Biology, 14469 Potsdam, Germany
| | - Cornelia U Welte
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands; Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands.
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126
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Lee H, Baek JI, Kim SJ, Kwon KK, Rha E, Yeom SJ, Kim H, Lee DH, Kim DM, Lee SG. Sensitive and Rapid Phenotyping of Microbes With Soluble Methane Monooxygenase Using a Droplet-Based Assay. Front Bioeng Biotechnol 2020; 8:358. [PMID: 32391352 PMCID: PMC7193049 DOI: 10.3389/fbioe.2020.00358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/31/2020] [Indexed: 12/22/2022] Open
Abstract
Methanotrophs with soluble methane monooxygenase (sMMO) show high potential for various ecological and biotechnological applications. Here, we developed a high throughput method to identify sMMO-producing microbes by integrating droplet microfluidics and a genetic circuit-based biosensor system. sMMO-producers and sensor cells were encapsulated in monodispersed droplets with benzene as the substrate and incubated for 5 h. The sensor cells were analyzed as the reporter for phenol-sensitive transcription activation of fluorescence. Various combinations of methanotrophs and biosensor cells were investigated to optimize the performance of our droplet-integrated transcriptional factor biosensor system. As a result, the conditions to ensure sMMO activity to convert the starting material, benzene, into phenol, were determined. The biosensor signals were sensitive and quantitative under optimal conditions, showing that phenol is metabolically stable within both cell species and accumulates in picoliter-sized droplets, and the biosensor cells are healthy enough to respond quantitatively to the phenol produced. These results show that our system would be useful for rapid evaluation of phenotypes of methanotrophs showing sMMO activity, while minimizing the necessity of time-consuming cultivation and enzyme preparation, which are required for conventional analysis of sMMO activity.
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Affiliation(s)
- Hyewon Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Ji In Baek
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, South Korea
| | - Su Jin Kim
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Kil Koang Kwon
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Eugene Rha
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Soo-Jin Yeom
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, South Korea
| | - Haseong Kim
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Dae-Hee Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
| | - Dong-Myung Kim
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, South Korea
| | - Seung-Goo Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, South Korea
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Chen Y, Wu C, Sung P, Chan SI, Chen PP. Turnover of a Methane Oxidation Tricopper Cluster Catalyst: Implications for the Mechanism of the Particulate Methane Monooxygenase (pMMO). ChemCatChem 2020. [DOI: 10.1002/cctc.202000322] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yu‐Hsuan Chen
- Department of ChemistryNational Chung Hsing University 145 Xingda Road South District Taichung 402 Taiwan
| | - Chang‐Quan Wu
- Department of ChemistryNational Chung Hsing University 145 Xingda Road South District Taichung 402 Taiwan
| | - Pei‐Hua Sung
- Department of ChemistryNational Chung Hsing University 145 Xingda Road South District Taichung 402 Taiwan
| | - Sunney I. Chan
- Institute of ChemistryAcademia Sinica 128 Academia Road Sec. 2, Nankang Taipei 11529 Taiwan
- Department of ChemistryNational Taiwan University No. 1, Sec. 4, Roosevelt Road Taipei 10617 Taiwan
| | - Peter Ping‐Yu Chen
- Department of ChemistryNational Chung Hsing University 145 Xingda Road South District Taichung 402 Taiwan
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Chu YX, Ma RC, Wang J, Zhu JT, Kang YR, He R. Effects of oxygen tension on the microbial community and functional gene expression of aerobic methane oxidation coupled to denitrification systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:12280-12292. [PMID: 31993906 DOI: 10.1007/s11356-020-07767-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
Aerobic CH4 oxidation coupled to denitrification (AME-D) can not only mitigate the emission of greenhouse gas (e.g., CH4) to the atmosphere, but also reduce NO3- and/or NO2- and alleviate nitrogen pollution. The effects of O2 tension on the community and functional gene expression of methanotrophs and denitrifiers were investigated in this study. Although higher CH4 oxidation occurred in the AME-D system with an initial O2 concentration of 21% (i.e., the O2-sufficient condition), more NO3--N was removed at the initial O2 concentration of 10% (i.e., the O2-limited environment). Type I methanotrophs, including Methylocaldum, Methylobacter, Methylococcus, Methylomonas, and Methylomicrobium, and type II methanotrophs, including Methylocystis and Methylosinus, dominated in the AME-D systems. Compared with type II methanotrophs, type I methanotrophs were more abundant in the AME-D systems. Proteobacteria and Actinobacteria were the main denitrifiers in the AME-D systems, and their compositions varied with the O2 tension. Quantitative PCR of the pmoA, nirS, and 16S rRNA genes showed that methanotrophs and denitrifiers were the main microorganisms in the AME-D systems, accounting for 46.4% and 24.1% in the O2-limited environment, respectively. However, the relative transcripts of the functional genes including pmoA, mmoX, nirK, nirS, and norZ were all less than 1%, especially the functional genes involved in denitrification under the O2-sufficient condition, likely due to the majority of the denitrifiers being dormant or even nonviable. These findings indicated that an optimal O2 concentration should be used to optimize the activity and functional gene expression of aerobic methanotrophs and denitrifiers in AME-D systems.
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Affiliation(s)
- Yi-Xuan Chu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo-Chan Ma
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jing Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jia-Tian Zhu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ya-Ru Kang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo He
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
- College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China.
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130
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Liu Y, He X, Zhu P, Cheng M, Hong Q, Yan X. pheS AG Based Rapid and Efficient Markerless Mutagenesis in Methylotuvimicrobium. Front Microbiol 2020; 11:441. [PMID: 32296398 PMCID: PMC7136838 DOI: 10.3389/fmicb.2020.00441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/02/2020] [Indexed: 01/05/2023] Open
Abstract
Due to their fast growth rate and robustness, some haloalkalitolerant methanotrophs from the genus Methylotuvimicrobium have recently become not only promising biocatalysts for methane conversion but also favorable materials for obtaining fundamental knowledge on methanotrophs. Here, to realize unmarked genome modification in Methylotuvimicrobium bacteria, a counterselectable marker (CSM) was developed based on pheS, which encodes the α-subunit of phenylalanyl-tRNA synthetase. Two-point mutations (T252A and A306G) were introduced into PheS in Methylotuvimicrobium buryatense 5GB1C, generating PheS AG , which can recognize p-chloro-phenylalanine (p-Cl-Phe) as a substrate. Theoretically, the expression of PheS AG in a cell will result in the incorporation of p-Cl-Phe into proteins, leading to cell death. The P tac promoter and the ribosome-binding site region of mmoX were employed to control pheS AG , producing the pheS AG -3 CSM. M. buryatense 5GB1C harboring pheS AG -3 was extremely sensitive to 0.5 mM p-Cl-Phe. Then, a positive and counterselection cassette, PZ (only 1.5 kb in length), was constructed by combining pheS AG -3 and the zeocin resistance gene. A PZ- and PCR-based strategy was used to create the unmarked deletion of glgA1 or the whole smmo operon in M. buryatense 5GB1C and Methylotuvimicrobium alcaliphilum 20Z. The positive rates were over 92%, and the process could be accomplished in as few as eight days.
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Affiliation(s)
- Yongchuang Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xiangrong He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Pingping Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Minggen Cheng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Qing Hong
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
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Kato S, Takashino M, Igarashi K, Kitagawa W. Isolation and Genomic Characterization of a Proteobacterial Methanotroph Requiring Lanthanides. Microbes Environ 2020; 35. [PMID: 32037377 PMCID: PMC7104280 DOI: 10.1264/jsme2.me19128] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Although the bioavailability of rare earth elements (REEs, including scandium, yttrium, and 15 lanthanides) has not yet been examined in detail, methane-oxidizing bacteria (methanotrophs) were recently shown to harbor specific types of methanol dehydrogenases (XoxF-MDHs) that contain lanthanides in their active site, whereas their well-characterized counterparts (MxaF-MDHs) were Ca2+-dependent. However, lanthanide dependency in methanotrophs has not been demonstrated, except in acidic environments in which the solubility of lanthanides is high. We herein report the isolation of a lanthanide-dependent methanotroph from a circumneutral environment in which lanthanides only slightly dissolved. Methanotrophs were enriched and isolated from pond sediment using mineral medium supplemented with CaCl2 or REE chlorides. A methanotroph isolated from the cerium (Ce) chloride-supplemented culture, Methylosinus sp. strain Ce-a6, was clearly dependent on lanthanide. Strain Ce-a6 only required approximately 30 nM lanthanide chloride for its optimal growth and exhibited the ability to utilize insoluble lanthanide oxides, which may enable survival in circumneutral environments. Genome and gene expression analyses revealed that strain Ce-a6 lost the ability to produce functional MxaF-MDH, and this may have been due to a large-scale deletion around the mxa gene cluster. The present results provide evidence for lanthanide dependency as a novel survival strategy by methanotrophs in circumneutral environments.
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Affiliation(s)
- Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University
| | - Motoko Takashino
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Wataru Kitagawa
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University.,Computational Bio Big Data Open Innovation Laboratory (CBBD-OIL), AIST
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132
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Naizabekov S, Lee EY. Genome-Scale Metabolic Model Reconstruction and in Silico Investigations of Methane Metabolism in Methylosinus trichosporium OB3b. Microorganisms 2020; 8:microorganisms8030437. [PMID: 32244934 PMCID: PMC7144005 DOI: 10.3390/microorganisms8030437] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 01/09/2023] Open
Abstract
Methylosinus trichosporium OB3b is an obligate aerobic methane-utilizing alpha-proteobacterium. Since its isolation, M. trichosporium OB3b has been established as a model organism to study methane metabolism in type II methanotrophs. M. trichosporium OB3b utilizes soluble and particulate methane monooxygenase (sMMO and pMMO respectively) for methane oxidation. While the source of electrons is known for sMMO, there is less consensus regarding electron donor to pMMO. To investigate this and other questions regarding methane metabolism, the genome-scale metabolic model for M. trichosporium OB3b (model ID: iMsOB3b) was reconstructed. The model accurately predicted oxygen: methane molar uptake ratios and specific growth rates on nitrate-supplemented medium with methane as carbon and energy source. The redox-arm mechanism which links methane oxidation with complex I of electron transport chain has been found to be the most optimal mode of electron transfer. The model was also qualitatively validated on ammonium-supplemented medium indicating its potential to accurately predict methane metabolism in different environmental conditions. Finally, in silico investigations regarding flux distribution in central carbon metabolism of M. trichosporium OB3b were performed. Overall, iMsOB3b can be used as an organism-specific knowledgebase and a platform for hypothesis-driven theoretical investigations of methane metabolism.
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Diversity of active root-associated methanotrophs of three emergent plants in a eutrophic wetland in northern China. AMB Express 2020; 10:48. [PMID: 32170424 PMCID: PMC7070141 DOI: 10.1186/s13568-020-00984-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 03/03/2020] [Indexed: 02/02/2023] Open
Abstract
Root-associated aerobic methanotrophs play an important role in regulating methane emissions from the wetlands. However, the influences of the plant genotype on root-associated methanotrophic structures, especially on active flora, remain poorly understood. Transcription of the pmoA gene, encoding particulate methane monooxygenase in methanotrophs, was analyzed by reverse transcription PCR (RT-PCR) of mRNA isolated from root samples of three emergent macrophytes, including Phragmites australis, Typha angustifolia, and Schoenoplectus triqueter (syn. Scirpus triqueter L.) from a eutrophic wetland. High-throughput sequencing of pmoA based on DNA and cDNA was used to analyze the methanotrophic community. Sequencing of cDNA pmoA amplicons confirmed that the structure of active methanotrophic was not always consistent with DNA. A type I methanotroph, Methylomonas, was the most active group in P. australis, whereas Methylocystis, a type II methanotroph, was the dominant group in S. triqueter. In T. angustifolia, these two types of methanotroph existed in similar proportions. However, at the DNA level, Methylomonas was predominant in the roots of all three plants. In addition, vegetation type could have a profound impact on root-associated methanotrophic community at both DNA and cDNA levels. These results indicate that members of the genera Methylomonas (type I) and Methylocystis (type II) can significantly contribute to aerobic methane oxidation in a eutrophic wetland.
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134
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Gafni A, Gelman F, Ronen Z, Bernstein A. Variable carbon and chlorine isotope fractionation in TCE co-metabolic oxidation. CHEMOSPHERE 2020; 242:125130. [PMID: 31669996 DOI: 10.1016/j.chemosphere.2019.125130] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Identifying co-metabolic TCE oxidation in polluted groundwater is challenging due to lack of indicative by-products. This challenge may theoretically be resolved if the oxidation process can be characterized by a distinct dual isotope enrichment. In this work, we aimed to explore the carbon and chlorine isotope effects associated with TCE oxidation by a variety of oxygenases. These included pure strains and enrichment cultures of methane, toluene and ammonia oxidizers, as well as experiments with crude extracts. Isotope effects determined for TCE oxidation by toluene and ammonia oxidizers were mostly in line with expected values for epoxidation mechanism (ϵ13C -11.0 ± 0.7 to -24.8 ± 0.2‰ and ϵ37Cl +0.9 ± 0.5 to +1.0 ± 0.4‰), whereas, the methanotrophs resulted in distinctively different isotope effects (ϵ13C -2.4 ± 0.4 to -3.4 ± 0.8‰ and ϵ37Cl -1.8 ± 0.2 to -2.9 ± 0.9‰). It is suggested that in TCE oxidation by methanotrophs, substrate binding rather than bond cleavage is rate limiting, leading to this unexpected isotope effect. On the environmental level, our results imply that the oxidative process can be differentiated if catalyzed by toluene and ammonia oxidizers or by methanotrophs. Additionally, the oxidative process can be distinguished from the reductive one. However, using dual isotope analysis in the field may result in an under-estimation of the overall co-metabolic process if methanotrophs are to be excluded due to low isotope effects.
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Affiliation(s)
- Almog Gafni
- Zuckerberg Institute for Water Research, Department of Environmental Hydrology and Microbiology, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Israel
| | - Faina Gelman
- Geological Survey of Israel, 32 Yesha'ayahu Leibowitz St, Jerusalem, 9692100, Israel
| | - Zeev Ronen
- Zuckerberg Institute for Water Research, Department of Environmental Hydrology and Microbiology, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Israel
| | - Anat Bernstein
- Zuckerberg Institute for Water Research, Department of Environmental Hydrology and Microbiology, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Israel.
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135
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He R, Su Y, Leewis MC, Chu YX, Wang J, Ma RC, Wu D, Zhan LT, Herriott IC, Leigh MB. Low O 2 level enhances CH 4-derived carbon flow into microbial communities in landfill cover soils. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113676. [PMID: 31818614 DOI: 10.1016/j.envpol.2019.113676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/07/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
Abstract
CH4 oxidation in landfill cover soils plays a significant role in mitigating CH4 release to the atmosphere. Oxygen availability and the presence of co-contaminants are potentially important factors affecting CH4 oxidation rate and the fate of CH4-derived carbon. In this study, microbial populations that oxidize CH4 and the subsequent conversion of CH4-derived carbon into CO2, soil organic C and biomass C were investigated in landfill cover soils at two O2 tensions, i.e., O2 concentrations of 21% ("sufficient") and 2.5% ("limited") with and without toluene. CH4-derived carbon was primarily converted into CO2 and soil organic C in the landfill cover soils, accounting for more than 80% of CH4 oxidized. Under the O2-sufficient condition, 52.9%-59.6% of CH4-derived carbon was converted into CO2 (CECO2-C), and 29.1%-39.3% was converted into soil organic C (CEorganic-C). A higher CEorganic-C and lower CECO2-C occurred in the O2-limited environment, relative to the O2-sufficient condition. With the addition of toluene, the carbon conversion efficiency of CH4 into biomass C and organic C increased slightly, especially in the O2-limited environment. A more complex microbial network was involved in CH4 assimilation in the O2-limited environment than under the O2-sufficient condition. DNA-based stable isotope probing of the community with 13CH4 revealed that Methylocaldum and Methylosarcina had a higher relative growth rate than other type I methanotrophs in the landfill cover soils, especially at the low O2 concentration, while Methylosinus was more abundant in the treatment with both the high O2 concentration and toluene. These results indicated that O2-limited environments could prompt more CH4-derived carbon to be deposited into soils in the form of biomass C and organic C, thereby enhancing the contribution of CH4-derived carbon to soil community biomass and functionality of landfill cover soils (i.e. reduction of CO2 emission).
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Affiliation(s)
- Ruo He
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
| | - Yao Su
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China; Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Mary-Cathrine Leewis
- Institute of Arctic Biology, University of Alaska Fairbanks, Alaska, 99775, USA; US Geological Survey, Menlo Park, CA, 94025, USA
| | - Yi-Xuan Chu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jing Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo-Chan Ma
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Donglei Wu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Liang-Tong Zhan
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | | | - Mary Beth Leigh
- Institute of Arctic Biology, University of Alaska Fairbanks, Alaska, 99775, USA
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Xing G, Garg S, Miller CJ, Pham AN, Waite TD. Effect of Chloride and Suwannee River Fulvic Acid on Cu Speciation: Implications to Cu Redox Transformations in Simulated Natural Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2334-2343. [PMID: 31999104 DOI: 10.1021/acs.est.9b06789] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Copper is a critical trace nutrient and, at higher concentrations, a toxicant in natural waters, with the relative rates of transformation between the Cu(I) and Cu(II) oxidation states being key to its speciation, bioavailability, and toxicity. While the influence of chloride (Cl-) and natural organic matter on Cu speciation and associated redox transformations has been studied separately, their combined influence on Cu speciation and Cu redox transformations has not been examined. As such, in this study, we investigate the impact of Cl- and Suwannee River fulvic acid (SRFA) on Cu(II) reduction and Cu(I) oxidation kinetics at pH 8.2. SRFA plays a dual role in providing Cu(II) reducing moieties as well as Cu ligating sites. Our results indicate that the SRFA-bound Cu(II) is less reactive than the inorganic Cu(II), and the SRFA-bound Cu(I) being much more rapidly oxidized than the inorganic Cu(I). The presence of Cl- weakens Cu(II) binding by SRFA, thereby increasing the reactivity of Cu(II). Similarly, weakening of Cu(I) binding by SRFA and concomitant binding of Cu(I) by Cl- stabilizes Cu(I). Our results further show that continuous formation of hydrogen peroxide occurs in the presence of Cu(II), SRFA, and Cl- in air-saturated solution with the presence of H2O2 enhancing the dynamic nature of the system.
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Affiliation(s)
- Guowei Xing
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Shikha Garg
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Christopher J Miller
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - A Ninh Pham
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - T David Waite
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
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137
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Cho S, Ha S, Kim HS, Han JH, Kim H, Yeon YJ, Na JG, Lee J. Stimulation of cell growth by addition of tungsten in batch culture of a methanotrophic bacterium, Methylomicrobium alcaliphilum 20Z on methane and methanol. J Biotechnol 2020; 309:81-84. [PMID: 31899249 DOI: 10.1016/j.jbiotec.2019.12.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/12/2019] [Accepted: 12/31/2019] [Indexed: 11/15/2022]
Abstract
It is carried out for researches to convert methane, the second most potent greenhouse gas, to high-value chemicals and fuels by using methanotrophs. In this study, we observed that cell growth of Methylomicrobium alcaliphilum 20Z in the batch cultures on methane or methanol was stimulated by the addition of tungsten (W) without formate accumulation. Not only biomass yield but also the total products yield (biomass and formate) on carbon basis increased up to 11.50-fold and 1.28-fold respectively in W-added medium. Furthermore, a significant decrease in CO2 yield from formate was observed in the W-added cells, which indicates that W might have affected the activity of certain enzymes involved in carbon assimilation as well as formate dehydrogenase (FDH). The results of this study suggest that M. alcaliphilum 20Z is a promising model system for studying the physiology of the aerobic methanotroph and for enabling its industrial use for methane conversion through high cell density cultivation.
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Affiliation(s)
- Sukhyeong Cho
- C1 Gas Refinery R&D Center, Sogang University, Seoul, Republic of Korea
| | - Seonyoung Ha
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Hye Su Kim
- C1 Gas Refinery R&D Center, Sogang University, Seoul, Republic of Korea
| | - Jin Hee Han
- C1 Gas Refinery R&D Center, Sogang University, Seoul, Republic of Korea
| | - Hyeonsoo Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Young Joo Yeon
- Department of Biochemical Engineering, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Jeong Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Jinwon Lee
- C1 Gas Refinery R&D Center, Sogang University, Seoul, Republic of Korea; Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea.
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138
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Nariya S, Kalyuzhnaya MG. Hemerythrins enhance aerobic respiration in Methylomicrobium alcaliphilum 20ZR, a methane-consuming bacterium. FEMS Microbiol Lett 2020; 367:5735436. [PMID: 32053143 DOI: 10.1093/femsle/fnaa003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/03/2020] [Indexed: 01/04/2023] Open
Abstract
Numerous hemerythrins, di-iron proteins, have been identified in prokaryote genomes, but in most cases their function remains elusive. Bacterial hemerythrin homologs (bacteriohemerythrins, Bhrs) may contribute to various cellular functions, including oxygen sensing, metal binding and antibiotic resistance. It has been proposed that methanotrophic Bhrs support methane oxidation by supplying oxygen to a core enzyme, particulate methane monooxygenase. In this study, the consequences of the overexpression or deletion of the Bhr gene (bhr) in Methylomicrobiam alcaliphillum 20ZR were investigated. We found that the bhrknockout (20ZRΔbhr) displays growth kinetics and methane consumption rates similar to wild type. However, the 20ZRΔbhr accumulates elevated concentrations of acetate at aerobic conditions, indicating slowed respiration. The methanotrophic strain overproducing Bhr shows increased oxygen consumption and reduced carbon-conversion efficiency, while its methane consumption rates remain unchanged. These results suggest that the methanotrophic Bhr proteins specifically contribute to oxygen-dependent respiration, while they have minimal, if any, input of oxygen for the methane oxidation machinery.
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Affiliation(s)
- Snehal Nariya
- Biology Department, 5500 Campanile Drive, San Diego, CA, USA
| | - Marina G Kalyuzhnaya
- Biology Department, 5500 Campanile Drive, San Diego, CA, USA.,Viral Information Institute, San Diego State University, 5500 Campanile Drive, San Diego, CA
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139
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Wang S, An Z, Wang ZW. Bioconversion of methane to chemicals and fuels by methane-oxidizing bacteria. ADVANCES IN BIOENERGY 2020. [DOI: 10.1016/bs.aibe.2020.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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140
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Reis PCJ, Thottathil SD, Ruiz-González C, Prairie YT. Niche separation within aerobic methanotrophic bacteria across lakes and its link to methane oxidation rates. Environ Microbiol 2019; 22:738-751. [PMID: 31769176 DOI: 10.1111/1462-2920.14877] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/23/2019] [Accepted: 11/22/2019] [Indexed: 11/30/2022]
Abstract
Lake methane (CH4 ) emissions are largely controlled by aerobic methane-oxidizing bacteria (MOB) which mostly belong to the classes Alpha- and Gammaproteobacteria (Alpha- and Gamma-MOB). Despite the known metabolic and ecological differences between the two MOB groups, their main environmental drivers and their relative contribution to CH4 oxidation rates across lakes remain unknown. Here, we quantified the two MOB groups through CARD-FISH along the water column of six temperate lakes and during incubations in which we measured ambient CH4 oxidation rates. We found a clear niche separation of Alpha- and Gamma-MOB across lake water columns, which is mostly driven by oxygen concentration. Gamma-MOB appears to dominate methanotrophy throughout the water column, but Alpha-MOB may also be an important player particularly in well-oxygenated bottom waters. The inclusion of Gamma-MOB cell abundance improved environmental models of CH4 oxidation rate, explaining part of the variation that could not be explained by environmental factors alone. Altogether, our results show that MOB composition is linked to CH4 oxidation rates in lakes and that information on the MOB community can help predict CH4 oxidation rates and thus emissions from lakes.
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Affiliation(s)
- Paula C J Reis
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, H2X 1Y4, Canada
| | - Shoji D Thottathil
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, H2X 1Y4, Canada
| | - Clara Ruiz-González
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), Barcelona, E-08003, Spain
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, H2X 1Y4, Canada
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141
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Laport MS, Pinheiro U, Rachid CTCDC. Freshwater Sponge Tubella variabilis Presents Richer Microbiota Than Marine Sponge Species. Front Microbiol 2019; 10:2799. [PMID: 31849922 PMCID: PMC6902092 DOI: 10.3389/fmicb.2019.02799] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/18/2019] [Indexed: 02/02/2023] Open
Abstract
Sponges can host diverse and abundant communities of microorganisms, which constitute an interesting source of bioactive compounds. Thus, to broaden our knowledge about the diversity of the microbiota that is found in freshwater sponges, the microbial community of Tubella variabilis was analyzed using culture-independent and culture-dependent approaches. Additionally, sponge-associated bacteria were compared with those living in the surrounding waters. Bacteria were also tested for antimicrobial production. Overall, the microbial composition identified comprises at least 44 phyla belonging mainly to Proteobacteria and low percentages of Bacteroidetes, Acidobacteria, and Verrucomicrobia. Alphaproteobacteria was the dominant class in T. variabilis while Betaproteobacteria was dominant in freshwater. Our data also revealed a high richness of bacteria in comparison to another freshwater sponge and 32 marine sponges. A global comparison of the structure of microbiota of different sponges showed that the main structuring factor may be the sponge environment, with T. variabilis and all freshwater sponges clustering together, and far away from the marine sponges. Bacterial strains from sponges and from freshwater were isolated and 163 morphotypes were phylogenetically identified. These belong to 26 genera, of which 12 were exclusively found in sponge samples and three only in freshwater. Inhibitory activities were also detected among 20–25% of the isolates from sponges and freshwater, respectively. This study presents new information on the composition of the microbial community found in freshwater sponges, which is diverse, abundant and distinct from some marine sponges. Moreover, the antimicrobial activity observed from the bacterial strains might play an important role in shaping microbial communities of the environment.
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Affiliation(s)
- Marinella Silva Laport
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ulisses Pinheiro
- Department of Zoology, Federal University of Pernambuco, Recife, Brazil
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142
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Pan J, Wang X, Cao A, Zhao G, Zhou C. Screening methane-oxidizing bacteria from municipal solid waste landfills and simulating their effects on methane and ammonia reduction. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:37082-37091. [PMID: 31745784 DOI: 10.1007/s11356-019-06545-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 09/16/2019] [Indexed: 06/10/2023]
Abstract
Municipal solid waste landfills are not only a crucial source of global greenhouse gas emissions; they also produce large amounts of ammonia (NH3), hydrogen sulfide, and other odorous gases that negatively affect the regional environment. Several types of methane-oxidizing bacteria (MOB) were proved to be effective in mitigating methane emission from landfills. Nevertheless, more MOB species and their technical parameters for best mitigating methane still need to be explored. In landfills, methane is simultaneously generated with ammonia, which may impede the CH4 bio-oxidizing process of MOB. However, very limited studies examined the enhancement of methane reduction by introducing ammonia-oxidizing bacteria (AOB) in landfills. In this study, two enriched MOB cultures were gained from a typical municipal solid waste landfill, and then were cultured with three strains of ammonia-oxidizing bacteria (AOB). The MOB enrichment culture used in this work includes Methylocaldum, Methylocystaceae, and Methyloversatilis, with a methane oxidation capacity of 43.6-65.0%, and the AOB includes Candida ethanolica, Bacillus cereus, and Alcaligenes faecalis. The effects on the emission reduction of both NH3 and CH4 were measured using self-made landfill-simulating equipment, as MOB, AOB, and a MOB-AOB mixture were added to the soil cover of the simulation equipment. The concentrations of CH4 and NH3 in the MOB-AOB mixture group decreased sharply, and the CH4 and NH3 concentration was 76.4% and 83.7% of the control group level. We also found that addition of AOB can help MOB oxidize CH4 and improve the emission reduction effect.
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Affiliation(s)
- Jingran Pan
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Xiaolin Wang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China
| | - Aixin Cao
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Guozhu Zhao
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China.
| | - Chuanbin Zhou
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
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143
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Xin JY, Sun LR, Lin HY, Zhang S, Xia CG. Hybridization of Particulate Methane Monooxygenase by Methanobactin-Modified AuNPs. Molecules 2019; 24:E4027. [PMID: 31703299 PMCID: PMC6891627 DOI: 10.3390/molecules24224027] [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: 10/10/2019] [Revised: 10/28/2019] [Accepted: 11/05/2019] [Indexed: 11/16/2022] Open
Abstract
Particulate methane monooxygenase (pMMO) is a characteristic membrane-bound metalloenzyme of methane-oxidizing bacteria that can catalyze the bioconversion of methane to methanol. However, in order to achieve pMMO-based continuous methane-to-methanol bioconversion, the problems of reducing power in vitro regeneration and pMMO stability need to be overcome. Methanobactin (Mb) is a small copper-chelating molecule that functions not only as electron carrier for pMMO catalysis and pMMO protector against oxygen radicals, but also as an agent for copper acquisition and uptake. In order to improve the activity and stability of pMMO, methanobactin-Cu (Mb-Cu)-modified gold nanoparticle (AuNP)-pMMO nanobiohybrids were straightforwardly synthesized via in situ reduction of HAuCl4 to AuNPs in a membrane fraction before further association with Mb-Cu. Mb-Cu modification can greatly improve the activity and stability of pMMO in the AuNP-pMMO nanobiohybrids. It is shown that the Mb-Cu-modified AuNP-pMMO nanobiohybrids can persistently catalyze the conversion of methane to methanol with hydroquinone as electron donor. The artificial heterogeneous nanobiohybrids exhibited excellent reusability and reproducibility in three cycles of catalysis, and they provide a model for achieving hydroquinone-driven conversion of methane to methanol.
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Affiliation(s)
- Jia-Ying Xin
- Key Laboratory of Food Science and Engineering, Harbin University of Commerce, Harbin 150076, China
- State Key Laboratory of Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Li-Rui Sun
- Key Laboratory of Food Science and Engineering, Harbin University of Commerce, Harbin 150076, China
| | - Hui-Ying Lin
- Key Laboratory of Food Science and Engineering, Harbin University of Commerce, Harbin 150076, China
| | - Shuai Zhang
- Key Laboratory of Food Science and Engineering, Harbin University of Commerce, Harbin 150076, China
| | - Chun-Gu Xia
- State Key Laboratory of Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
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144
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Chen H, Luo J, Liu S, Yuan Z, Guo J. Microbial Methane Conversion to Short-Chain Fatty Acids Using Various Electron Acceptors in Membrane Biofilm Reactors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:12846-12855. [PMID: 31593452 DOI: 10.1021/acs.est.8b06767] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Given our vast methane reserves and the forecasted shortage of crude oil in the not too distant future, the conversion of methane into value-added liquid chemicals or fuels would be beneficial. The generated chemicals or fuels could augment the petroleum-dominated chemical market, and also satisfy the increasing demand for transportation fuels. While methane bioconversion to liquid chemicals has just been reported recently, there is limited understanding of the process. This study aims to clarify the potential electron acceptors that could support the process. Here we operated four membrane biofilm reactors (MBfRs) fed with nitrate, nitrite, oxygen at a relatively low rate, and oxygen at a relatively high rate, respectively, to study if they can support methane bioconversion to short-chain fatty acids (SCFAs) and the associated microbiological features. All tested electron acceptors facilitated methane bioconversion to SCFAs (ranging from 1.1 to 36.7 mg acetate L-1 d-1, or 3.4 to 114.6 mg acetate d-1 m-2 of biofilm). The carbon efficiency was estimated to be 7.9 ± 1.4% to 148.5 ± 1.3%, with an efficiency higher than 100%, suggesting the assimilation of other carbon, very likely CO2, into the products. A low oxygen supply rate of 46.4 ± 2.3 mg O2 d-1 m-2 was found to be the most favorable among all the electron conditions provided according to the SCFAs production rate and also the carbon utilization efficiency. Microbial characterization revealed that completely different communities evolved in the respective reactors, suggesting diverse microbial pathways exist for methane bioconversion into value-added chemicals.
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Affiliation(s)
- Hui Chen
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
| | - Jinghuan Luo
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
| | - Shuai Liu
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
| | - Jianhua Guo
- Advanced Water Management Centre , The University of Queensland , St Lucia , Queensland 4072 , Australia
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145
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Profiling Bacterial Diversity and Potential Pathogens in Wastewater Treatment Plants Using High-Throughput Sequencing Analysis. Microorganisms 2019; 7:microorganisms7110506. [PMID: 31671809 PMCID: PMC6921039 DOI: 10.3390/microorganisms7110506] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/23/2019] [Accepted: 10/09/2019] [Indexed: 12/03/2022] Open
Abstract
Next-generation sequencing provides new insights into the diversity and structure of bacterial communities, as well as the fate of pathogens in wastewater treatment systems. In this study, the bacterial community structure and the presence of pathogenic bacteria in three wastewater treatment plants across Gauteng province in South Africa were studied. The physicochemical results indicated that the quality of wastewater varies considerably from one plant to the others. Proteobacteria, Actinobacteria, Firmicutes, and Chloroflexi were the dominant phyla across the three wastewater treatment plants, while Alphaproteobacteria, Actinobacteria, Bacilli, and Clostridia were the dominant classes. The dominant bacterial functions were highly associated with carbohydrate, energy, and amino acid metabolism. In addition, potential pathogenic bacterial members identified from the influent/effluent samples included Roseomonas, Bacillus, Pseudomonas, Clostridium, Mycobacterium, Methylobacterium, and Aeromonas. The results of linear discriminant analysis (LDA) effect size analysis also confirmed that these bacterial pathogens were significantly abundant in the wastewater treatment systems. Further, the results of this study highlighted that the presence of bacterial pathogens in treated effluent pose a potential contamination risk, transmitted through soil, agriculture, water, or sediments. There is thus a need for continuous monitoring of potential pathogens in wastewater treatment plants (WWTPs) in order to minimize public health risk.
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146
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Mohammadi SS, Schmitz RA, Pol A, Berben T, Jetten MSM, Op den Camp HJM. The Acidophilic Methanotroph Methylacidimicrobium tartarophylax 4AC Grows as Autotroph on H 2 Under Microoxic Conditions. Front Microbiol 2019; 10:2352. [PMID: 31681216 PMCID: PMC6813726 DOI: 10.3389/fmicb.2019.02352] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 09/27/2019] [Indexed: 12/17/2022] Open
Abstract
Emissions of the strong greenhouse gas methane (CH4) to the atmosphere are mitigated by methanotrophic microorganisms. Methanotrophs found in extremely acidic geothermal systems belong to the phylum Verrucomicrobia. Thermophilic verrucomicrobial methanotrophs from the genus Methylacidiphilum can grow autotrophically on hydrogen gas (H2), but it is unknown whether this also holds for their mesophilic counterparts from the genus Methylacidimicrobium. To determine this, we examined H2 consumption and CO2 fixation by the mesophilic verrucomicrobial methanotroph Methylacidimicrobium tartarophylax 4AC. We found that strain 4AC grows autotrophically on H2 with a maximum growth rate of 0.0048 h–1 and a yield of 2.1 g dry weight⋅mol H2–1, which is about 12 and 41% compared to the growth rate and yield on methane, respectively. The genome of strain 4AC only encodes for an oxygen-sensitive group 1b [NiFe] hydrogenase and H2 is respired only when oxygen concentrations are below 40 μM. Phylogenetic analysis and genomic comparison of methanotrophs revealed diverse [NiFe] hydrogenases, presumably with varying oxygen sensitivity and affinity for H2, which could drive niche differentiation. Our results show that both thermophilic and mesophilic verrucomicrobial methanotrophs can grow as autotrophs on H2 as a sole energy source. Our results suggest that verrucomicrobial methanotrophs are particularly well-equipped to thrive in hostile volcanic ecosystems, since they can consume H2 as additional energy source.
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Affiliation(s)
- Sepehr S Mohammadi
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Tom Berben
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
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147
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Khoshnevisan B, Tsapekos P, Zhang Y, Valverde-Pérez B, Angelidaki I. Urban biowaste valorization by coupling anaerobic digestion and single cell protein production. BIORESOURCE TECHNOLOGY 2019; 290:121743. [PMID: 31323514 DOI: 10.1016/j.biortech.2019.121743] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/28/2019] [Accepted: 06/29/2019] [Indexed: 06/10/2023]
Abstract
Resource efficient and novel practices to produce proteinaceous food and feed sources can partially alleviate the protein scarcity problem. The conversion of low-value waste streams into single cell protein (SCP) seems a potent solution. This study evaluated the possibility of urban biowaste valorization through coupling anaerobic digestion and SCP production, and feeding a methanotroph mixed-culture with raw and upgraded biogas. In respect to nitrogen supply, the mixed-culture could grow well providing nutrients by direct addition of pasteurized centrifuged-filtered digestate or by adding electrochemically extracted ammonium from the digestate. The SCP yield on methane varied from 0.59 to 0.76 g cell dry weight (CDW)/g CH4. A high yield on methane (0.87 g CDW/g CH4) proved that biogas is a good substitute for natural gas for scaled-up microbial protein production. In addition, the produced SCP was rich in essential amino acids, marking the produced biomass comparable with other protein sources.
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Affiliation(s)
- Benyamin Khoshnevisan
- Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby, Denmark; Department of Mechanical Engineering of Agricultural Machinery, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Iran
| | - Panagiotis Tsapekos
- Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby, Denmark
| | - Yifeng Zhang
- Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby, Denmark
| | - Borja Valverde-Pérez
- Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby, Denmark
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby, Denmark.
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148
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Reddy KR, Rai RK, Green SJ, Chetri JK. Effect of temperature on methane oxidation and community composition in landfill cover soil. J Ind Microbiol Biotechnol 2019; 46:1283-1295. [PMID: 31317292 DOI: 10.1061/(asce)ee.1943-7870.0001712] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 07/11/2019] [Indexed: 05/26/2023]
Abstract
Municipal solid waste (MSW) landfills are the third largest anthropogenic source of methane (CH4) emissions in the United States. The majority of CH4 generated in landfills is converted to carbon dioxide (CO2) by CH4-oxidizing bacteria (MOB) present in the landfill cover soil, whose activity is controlled by various environmental factors including temperature. As landfill temperature can fluctuate substantially seasonally, rates of CH4 oxidation can also vary, and this could lead to incomplete oxidation. This study aims at analyzing the effect of temperature on CH4 oxidation potential and microbial community structure of methanotrophs in laboratory-based studies of landfill cover soil and cultivated consortia. Soil and enrichment cultures were incubated at temperatures ranging from 6 to 70 °C, and rates of CH4 oxidation were measured, and the microbial community structure was analyzed using 16S rRNA gene amplicon sequencing and shotgun metagenome sequencing. CH4 oxidation occurred at temperatures from 6 to 50 °C in soil microcosm tests, and 6-40 °C in enrichment culture batch tests; maximum rates of oxidation were obtained at 30 °C. A corresponding shift in the soil microbiota was observed, with a transition from putative psychrophilic to thermophilic methanotrophs with increasing incubation temperature. A strong shift in methanotrophic community structure was observed above 30 °C. At temperatures up to 30 °C, methanotrophs from the genus Methylobacter were dominant in soils and enrichment cultures; at a temperature of 40 °C, putative thermophilic methanotrophs from the genus Methylocaldum become dominant. Maximum rate measurements of nearly 195 μg CH4 g-1 day-1 were observed in soil incubations, while observed maximum rates in enrichments were significantly lower, likely as a result of diffusion limitations. This study demonstrates that temperature is a critical factor affecting rates of landfill soil CH4 oxidation in vitro and that changing rates of CH4 oxidation are in part driven by changes in methylotroph community structure.
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Affiliation(s)
- Krishna R Reddy
- Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL, 60607, USA.
| | - Raksha K Rai
- Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL, 60607, USA
| | - Stefan J Green
- Department of Biological Sciences, Sequencing Core, Resources Center, University of Illinois at Chicago, 835 S. Wolcott, Chicago, IL, 60612, USA
| | - Jyoti K Chetri
- Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL, 60607, USA
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149
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Crevecoeur S, Ruiz-González C, Prairie YT, Del Giorgio PA. Large-scale biogeography and environmental regulation of methanotrophic bacteria across boreal inland waters. Mol Ecol 2019; 28:4181-4196. [PMID: 31479544 DOI: 10.1111/mec.15223] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/01/2019] [Accepted: 08/06/2019] [Indexed: 01/09/2023]
Abstract
Aerobic methanotrophic bacteria (methanotrophs) use methane as a source of carbon and energy, thereby mitigating net methane emissions from natural sources. Methanotrophs represent a widespread and phylogenetically complex guild, yet the biogeography of this functional group and the factors that explain the taxonomic structure of the methanotrophic assemblage are still poorly understood. Here, we used high-throughput sequencing of the 16S rRNA gene of the bacterial community to study the methanotrophic community composition and the environmental factors that influence their distribution and relative abundance in a wide range of freshwater habitats, including lakes, streams and rivers across the boreal landscape. Within one region, soil and soil water samples were additionally taken from the surrounding watersheds in order to cover the full terrestrial-aquatic continuum. The composition of methanotrophic communities across the boreal landscape showed only a modest degree of regional differentiation but a strong structuring along the hydrologic continuum from soil to lake communities, regardless of regions. This pattern along the hydrologic continuum was mostly explained by a clear niche differentiation between type I and type II methanotrophs along environmental gradients in pH, and methane concentrations. Our results suggest very different roles of type I and type II methanotrophs within inland waters, the latter likely having a terrestrial source and reflecting passive transport and dilution along the aquatic networks, but this is an unresolved issue that requires further investigation.
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Affiliation(s)
- Sophie Crevecoeur
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada
| | - Clara Ruiz-González
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada
| | - Paul A Del Giorgio
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada
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150
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Semrau JD, DiSpirito AA. Methanobactin: A Novel Copper-Binding Compound Produced by Methanotrophs. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/978-3-030-23261-0_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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