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Ahmadi F, Lackner M. Recent findings in methanotrophs: genetics, molecular ecology, and biopotential. Appl Microbiol Biotechnol 2024; 108:60. [PMID: 38183483 DOI: 10.1007/s00253-023-12978-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/08/2023] [Accepted: 10/01/2023] [Indexed: 01/08/2024]
Abstract
The potential consequences for mankind could be disastrous due to global warming, which arises from an increase in the average temperature on Earth. The elevation in temperature primarily stems from the escalation in the concentration of greenhouse gases (GHG) such as CO2, CH4, and N2O within the atmosphere. Among these gases, methane (CH4) is particularly significant in driving alterations to the worldwide climate. Methanotrophic bacteria possess the distinctive ability to employ methane as both as source of carbon and energy. These bacteria show great potential as exceptional biocatalysts in advancing C1 bioconversion technology. The present review describes recent findings in methanotrophs including aerobic and anaerobic methanotroph bacteria, phenotypic characteristics, biotechnological potential, their physiology, ecology, and native multi-carbon utilizing pathways, and their molecular biology. The existing understanding of methanogenesis and methanotrophy in soil, as well as anaerobic methane oxidation and methanotrophy in temperate and extreme environments, is also covered in this discussion. New types of methanogens and communities of methanotrophic bacteria have been identified from various ecosystems and thoroughly examined for a range of biotechnological uses. Grasping the processes of methanogenesis and methanotrophy holds significant importance in the development of innovative agricultural techniques and industrial procedures that contribute to a more favorable equilibrium of GHG. This current review centers on the diversity of emerging methanogen and methanotroph species and their effects on the environment. By amalgamating advanced genetic analysis with ecological insights, this study pioneers a holistic approach to unraveling the biopotential of methanotrophs, offering unprecedented avenues for biotechnological applications. KEY POINTS: • The physiology of methanotrophic bacteria is fundamentally determined. • Native multi-carbon utilizing pathways in methanotrophic bacteria are summarized. • The genes responsible for encoding methane monooxygenase are discussed.
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Affiliation(s)
- Fatemeh Ahmadi
- School of Agriculture and Environment, University of Western Australia, Crawley, 6009, Australia
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, 7001, Australia
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He L, Lidstrom ME. Utilisation of low methane concentrations by methanotrophs. Adv Microb Physiol 2024; 85:57-96. [PMID: 39059823 DOI: 10.1016/bs.ampbs.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
The growing urgency regarding climate change points to methane as a key greenhouse gas for slowing global warming to allow other mitigation measures to take effect. One approach to both decreasing methane emissions and removing methane from air is aerobic methanotrophic bacteria, those bacteria that grow on methane as sole carbon and energy source and require O2. A subset of these methanotrophs is able to grow on methane levels of 1000 parts per million (ppm) and below, and these present an opportunity for developing both environmental- and bioreactor-based methane treatment systems. However, relatively little is known about the traits of such methanotrophs that allow them to grow on low methane concentrations. This review assesses current information regarding how methanotrophs grow on low methane concentrations in the context of developing treatment strategies that could be applied for both decreasing methane emissions and removing methane from air.
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Affiliation(s)
- Lian He
- Department of Chemical Engineering, University of Washington, Seattle, WA United States
| | - Mary E Lidstrom
- Department of Chemical Engineering, University of Washington, Seattle, WA United States; Department of Microbiology, University of Washington, Seattle, WA United States.
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Xing Z, Chen S, Xu F, Su X, Gou F, Shi Y, Chen H, Xiang J, Li J, Zhao T. Quantitative analysis of TCE biodegradation pathway in landfill cover utilizing continuous monitoring, droplet digital PCR and multi-omics sequencing technology. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118509. [PMID: 37413727 DOI: 10.1016/j.jenvman.2023.118509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 07/08/2023]
Abstract
The remediation of volatile chlorinated hydrocarbons in the quasi-vadose zone has become a significant challenge. We applied an integrated approach to assess the biodegradability of trichloroethylene to identify the biotransformation mechanism. The formation of the functional zone biochemical layer was assessed by analyzing the distribution of landfill gas, physical and chemical properties of cover soil, spatial-temporal variations of micro-ecology, biodegradability of landfill cover soil and distributional difference metabolic pathway. Real-time online monitoring showed that trichloroethylene continuously undergoes anaerobic dichlorination and simultaneous aerobic/anaerobic conversion-aerobic co-metabolic degradation on the vertical gradient of the landfill cover system and reduction in trans-1,2-dichloroethylene in the anoxic zone but not 1,1-dichloroethylene. PCR and diversity sequencing revealed the abundance and spatial distribution of known dichlorination-related genes within the landfill cover, with 6.61 ± 0.25 × 104-6.78 ± 0.09 × 106 and 1.17 ± 0.78 × 103-7.82 ± 0.07 × 105 copies per g/soil of pmoA and tceA, respectively. In addition, dominant bacteria and diversity were significantly linked with physicochemical factors, and Mesorhizobium, Pseudoxanthomonas and Gemmatimonas were responsible for biodegradation in the aerobic, anoxic and anaerobic zones. Metagenome sequencing identified 6 degradation pathways of trichloroethylene that may occur in the landfill cover; the main pathway was incomplete dechlorination accompanied by cometabolic degradation. These results indicate that the anoxic zone is important for trichloroethylene degradation.
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Affiliation(s)
- Zhilin Xing
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
| | - Shangjie Chen
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Fuqing Xu
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Xia Su
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Fang Gou
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Yunchun Shi
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Hao Chen
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Jinxin Xiang
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Juan Li
- Chongqing Academy of Chinese Materia Medica, Chongqing, 400060, China
| | - Tiantao Zhao
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
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He L, Groom JD, Wilson EH, Fernandez J, Konopka MC, Beck DAC, Lidstrom ME. A methanotrophic bacterium to enable methane removal for climate mitigation. Proc Natl Acad Sci U S A 2023; 120:e2310046120. [PMID: 37603746 PMCID: PMC10466089 DOI: 10.1073/pnas.2310046120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/19/2023] [Indexed: 08/23/2023] Open
Abstract
The rapid increase of the potent greenhouse gas methane in the atmosphere creates great urgency to develop and deploy technologies for methane mitigation. One approach to removing methane is to use bacteria for which methane is their carbon and energy source (methanotrophs). Such bacteria naturally convert methane to CO2 and biomass, a value-added product and a cobenefit of methane removal. Typically, methanotrophs grow best at around 5,000 to 10,000 ppm methane, but methane in the atmosphere is 1.9 ppm. Air above emission sites such as landfills, anaerobic digestor effluents, rice paddy effluents, and oil and gas wells contains elevated methane in the 500 ppm range. If such sites are targeted for methane removal, technology harnessing aerobic methanotroph metabolism has the potential to become economically and environmentally viable. The first step in developing such methane removal technology is to identify methanotrophs with enhanced ability to grow and consume methane at 500 ppm and lower. We report here that some existing methanotrophic strains grow well at 500 ppm methane, and one of them, Methylotuvimicrobium buryatense 5GB1C, consumes such low methane at enhanced rates compared to previously published values. Analyses of bioreactor-based performance and RNAseq-based transcriptomics suggest that this ability to utilize low methane is based at least in part on extremely low non-growth-associated maintenance energy and on high methane specific affinity. This bacterium is a candidate to develop technology for methane removal at emission sites. If appropriately scaled, such technology has the potential to slow global warming by 2050.
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Affiliation(s)
- Lian He
- Department of Chemical Engineering, University of Washington, Seattle, WA98195
| | - Joseph D. Groom
- Department of Chemical Engineering, University of Washington, Seattle, WA98195
| | - Erin H. Wilson
- School of Computer Science & Engineering, University of Washington, Seattle, WA98195
| | | | | | - David A. C. Beck
- Department of Chemical Engineering, University of Washington, Seattle, WA98195
- eScience Institute, University of Washington, Seattle, WA98195
| | - Mary E. Lidstrom
- Department of Chemical Engineering, University of Washington, Seattle, WA98195
- Department of Microbiology, University of Washington, Seattle, WA98195
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