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Wen P, Tang J, Wang Y, Liu X, Yu Z, Zhou S. Hyperthermophilic composting significantly decreases methane emissions: Insights into the microbial mechanism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147179. [PMID: 33894609 DOI: 10.1016/j.scitotenv.2021.147179] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/28/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Methane (CH4) emissions from thermophilic composting (TC) are a substantial contributor to climate change. Hyperthermophilic composting (HTC) can influence CH4-related microbial communities at temperatures up to 80 °C, and thus impact the CH4 emissions during composting. This work investigated CH4 emissions in sludge-derived HTC, and explored microbial community succession with quantitative PCR and high-throughput sequencing. Results demonstrated that HTC decreased CH4 emissions by 52.5% compared with TC. In HTC, the CH4 production potential and CH4 oxidation potential were nearly 40% and 64.1% lower than that of TC, respectively. There was a reduction in the quantity of mcrA (3.7 × 108 to 0 g-1 TS) in HTC, which was more significant than the reduction in pmoA (2.0 × 105 to 2.1 × 104 g-1 TS), and thus lead to reduce CH4 emissions. It was found that the abundance of most methanogens and methanotrophs was inhibited in the hyperthermal environment, with a decline in Methanosarcina, Methanosaeta and Methanobrevibacter potentially being responsible for reducing the CH4 emissions in HTC. This work provides important insight into mitigating CH4 emissions in composting.
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Affiliation(s)
- Ping Wen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Jia Tang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Yueqiang Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiaoming Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Zhen Yu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
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Choi M, Yun T, Song MJ, Kim J, Lee BH, Löffler FE, Yoon S. Cometabolic Vinyl Chloride Degradation at Acidic pH Catalyzed by Acidophilic Methanotrophs Isolated from Alpine Peat Bogs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5959-5969. [PMID: 33843227 DOI: 10.1021/acs.est.0c08766] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Remediation of toxic chlorinated ethenes via microbial reductive dechlorination can lead to ethene formation; however, the process stalls in acidic groundwater, leading to the accumulation of carcinogenic vinyl chloride (VC). This study explored the feasibility of cometabolic VC degradation by moderately acidophilic methanotrophs. Two novel isolates, Methylomonas sp. strain JS1 and Methylocystis sp. strain MJC1, were obtained from distinct alpine peat bogs located in South Korea. Both isolates cometabolized VC with CH4 as the primary substrate under oxic conditions at pH at or below 5.5. VC cometabolism in axenic cultures occurred in the presence (10 μM) or absence (<0.01 μM) of copper, suggesting that VC removal had little dependence on copper availability, which regulates expression and activity of soluble and particulate methane monooxygenases in methanotrophs. The model neutrophilic methanotroph Methylosinus trichosporium strain OB3b also grew and cometabolized VC at pH 5.0 regardless of copper availability. Bioaugmentation of acidic peat soil slurries with methanotroph isolates demonstrated enhanced VC degradation and VC consumption below the maximum concentration level of 2 μg L-1. Community profiling of the microcosms suggested species-specific differences, indicating that robust bioaugmentation with methanotroph cultures requires further research.
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Affiliation(s)
- Munjeong Choi
- Department of Civil and Environmental Engineering, KAIST, Daejeon 34141, South Korea
| | - Taeho Yun
- Department of Civil and Environmental Engineering, KAIST, Daejeon 34141, South Korea
| | - Min Joon Song
- Department of Civil and Environmental Engineering, KAIST, Daejeon 34141, South Korea
| | - Jisun Kim
- Department of Civil and Environmental Engineering, KAIST, Daejeon 34141, South Korea
| | - Byoung-Hee Lee
- Microorganism Resources Division, National Institute of Biological Resources, NIBR, Incheon 22689, South Korea
| | - Frank E Löffler
- Center for Environmental Biotechnology, Department of Microbiology, Department of Civil and Environmental Engineering, Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee 37996, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sukhwan Yoon
- Department of Civil and Environmental Engineering, KAIST, Daejeon 34141, South Korea
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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: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/04/2020] [Accepted: 01/20/2021] [Indexed: 10/22/2022]
Abstract
Methane, the predominant element in natural gas and biogas, represents a promising alternative to carbon feedstocks in the biotechnological industry due to its low cost and high abundance. The bioconversion of methane to value-added products can enhance the value of gas and mitigate greenhouse gas emissions. Methanotrophs, methane-utilizing bacteria, can make a significant contribution to the production of various valuable biofuels and chemicals from methane. Type II methanotrophs in comparison with Type I methanotrophs have distinct advantages, including high acetyl-CoA flux and the co-incorporation of two important greenhouse gases (methane and CO2), making it a potential microbial cell-factory platform for methane-derived biomanufacturing. Herein, we review the most recent advances in Type II methanotrophs related to multi-omics studies and metabolic engineering. Representative examples and prospects of metabolic engineering strategies for the production of suitable products are also discussed.
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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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Abstract
Aerobic methanotrophs have long been known to play a critical role in the global carbon cycle, being capable of converting methane to biomass and carbon dioxide. Interestingly, these microbes exhibit great sensitivity to copper and rare-earth elements, with the expression of key genes involved in the central pathway of methane oxidation controlled by the availability of these metals. That is, these microbes have a "copper switch" that controls the expression of alternative methane monooxygenases and a "rare-earth element switch" that controls the expression of alternative methanol dehydrogenases. Further, it has been recently shown that some methanotrophs can detoxify inorganic mercury and demethylate methylmercury; this finding is remarkable, as the canonical organomercurial lyase does not exist in these methanotrophs, indicating that a novel mechanism is involved in methylmercury demethylation. Here, we review recent findings on methanotrophic interactions with metals, with a particular focus on these metal switches and the mechanisms used by methanotrophs to bind and sequester metals.
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Kalyuzhnaya MG, Puri AW, Lidstrom ME. Metabolic engineering in methanotrophic bacteria. Metab Eng 2015; 29:142-152. [PMID: 25825038 DOI: 10.1016/j.ymben.2015.03.010] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/26/2015] [Accepted: 03/17/2015] [Indexed: 12/19/2022]
Abstract
Methane, as natural gas or biogas, is the least expensive source of carbon for (bio)chemical synthesis. Scalable biological upgrading of this simple alkane to chemicals and fuels can bring new sustainable solutions to a number of industries with large environmental footprints, such as natural gas/petroleum production, landfills, wastewater treatment, and livestock. Microbial biocatalysis with methane as a feedstock has been pursued off and on for almost a half century, with little enduring success. Today, biological engineering and systems biology provide new opportunities for metabolic system modulation and give new optimism to the concept of a methane-based bio-industry. Here we present an overview of the most recent advances pertaining to metabolic engineering of microbial methane utilization. Some ideas concerning metabolic improvements for production of acetyl-CoA and pyruvate, two main precursors for bioconversion, are presented. We also discuss main gaps in the current knowledge of aerobic methane utilization, which must be solved in order to release the full potential of methane-based biosystems.
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Affiliation(s)
- Marina G Kalyuzhnaya
- Biology Department, San Diego State University, San Diego, CA 92182-4614, United States; Department of Microbiology, University of Washington, Seattle, WA 98195, United States
| | - Aaron W Puri
- Department of Chemical Engineering, Seattle, WA 98195, United States
| | - Mary E Lidstrom
- Department of Chemical Engineering, Seattle, WA 98195, United States; Department of Microbiology, University of Washington, Seattle, WA 98195, United States.
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Semrau JD. Bioremediation via Methanotrophy: Overview of Recent Findings and Suggestions for Future Research. Front Microbiol 2011; 2:209. [PMID: 22016748 PMCID: PMC3191459 DOI: 10.3389/fmicb.2011.00209] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 09/24/2011] [Indexed: 01/17/2023] Open
Abstract
Microbially mediated bioremediation of polluted sites has been a subject of much research over the past 30 years, with many different compounds shown to be degraded under both aerobic and anaerobic conditions. Aerobic-mediated bioremediation commonly examines the use of methanotrophs, microorganisms that consume methane as their sole source of carbon and energy. Given the diverse environments in which methanotrophs have been found, the range of substrates they can degrade and the fact that they can be easily stimulated with the provision of methane and oxygen, these microorganisms in particular have been examined for aerobic degradation of chlorinated hydrocarbons. The physiological and phylogenetic diversity of methanotrophy, however, has increased substantially in just the past 5 years. Here in this review, the current state of knowledge of methanotrophy, particularly as it applies to pollutant degradation is summarized, and suggestions for future research provided.
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Affiliation(s)
- Jeremy D Semrau
- Department of Civil and Environmental Engineering, The University of Michigan Ann Arbor, MI, USA
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Yoon S, Im J, Bandow N, Dispirito AA, Semrau JD. Constitutive expression of pMMO by Methylocystis strain SB2 when grown on multi-carbon substrates: implications for biodegradation of chlorinated ethenes. ENVIRONMENTAL MICROBIOLOGY REPORTS 2011; 3:182-188. [PMID: 23761250 DOI: 10.1111/j.1758-2229.2010.00205.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The particulate methane monooxygenase (pMMO) in Methylocystis strain SB2 was found to be constitutively expressed in the absence of methane when the strain was grown on either acetate or ethanol. Real-time quantitative polymerase chain reaction (PCR) and reverse transcription-PCR showed that the expression of pmoA decreased by one to two orders of magnitude when grown on acetate as compared with growth of strain SB2 on methane. The capability of strain SB2 to degrade a mixture of chlorinated ethenes in the absence of methane was examined to verify the presence and activity of pMMO under acetate-growth conditions as well determine the effectiveness of such conditions for bioremediation. It was found that when strain SB2 was grown on acetate and exposed to 40 µM each of trichloroethylene (TCE), trans-dichloroethylene (t-DCE) and vinyl chloride (VC), approximately 30% of VC and t-DCE was degraded but no appreciable TCE removal was measured after 216 h of incubation. The ability to degrade VC and t-DCE was lost when acetylene was added, confirming that pMMO was responsible for the degradation of these chlorinated ethenes by Methylocystis strain SB2 when the strain was grown on acetate.
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Affiliation(s)
- Sukhwan Yoon
- Department of Civil and Environmental Engineering, The University of Michigan, 1351 Beal Avenue, Ann Arbor, MI 48109-2125, USA. Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011-3211, USA
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Proteomic and targeted qPCR analyses of subsurface microbial communities for presence of methane monooxygenase. Biodegradation 2011; 22:1045-59. [DOI: 10.1007/s10532-011-9462-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 02/17/2011] [Indexed: 01/21/2023]
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Abstract
Methanotrophs, cells that consume methane (CH(4)) as their sole source of carbon and energy, play key roles in the global carbon cycle, including controlling anthropogenic and natural emissions of CH(4), the second-most important greenhouse gas after carbon dioxide. These cells have also been widely used for bioremediation of chlorinated solvents, and help sustain diverse microbial communities as well as higher organisms through the conversion of CH(4) to complex organic compounds (e.g. in deep ocean and subterranean environments with substantial CH(4) fluxes). It has been well-known for over 30 years that copper (Cu) plays a key role in the physiology and activity of methanotrophs, but it is only recently that we have begun to understand how these cells collect Cu, the role Cu plays in CH(4) oxidation by the particulate CH(4) monooxygenase, the effect of Cu on the proteome, and how Cu affects the ability of methanotrophs to oxidize different substrates. Here we summarize the current state of knowledge of the phylogeny, environmental distribution, and potential applications of methanotrophs for regional and global issues, as well as the role of Cu in regulating gene expression and proteome in these cells, its effects on enzymatic and whole-cell activity, and the novel Cu uptake system used by methanotrophs.
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Affiliation(s)
- Jeremy D Semrau
- Department of Civil and Environmental Engineering, The University of Michigan, Ann Arbor, MI, USA.
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Yoon S, Carey JN, Semrau JD. Feasibility of atmospheric methane removal using methanotrophic biotrickling filters. Appl Microbiol Biotechnol 2009; 83:949-56. [DOI: 10.1007/s00253-009-1977-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/08/2009] [Accepted: 03/18/2009] [Indexed: 10/20/2022]
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