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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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2
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Samanta D, Rauniyar S, Saxena P, Sani RK. From genome to evolution: investigating type II methylotrophs using a pangenomic analysis. mSystems 2024; 9:e0024824. [PMID: 38695578 DOI: 10.1128/msystems.00248-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/04/2024] [Indexed: 06/19/2024] Open
Abstract
A comprehensive pangenomic approach was employed to analyze the genomes of 75 type II methylotrophs spanning various genera. Our investigation revealed 256 exact core gene families shared by all 75 organisms, emphasizing their crucial role in the survival and adaptability of these organisms. Additionally, we predicted the functionality of 12 hypothetical proteins. The analysis unveiled a diverse array of genes associated with key metabolic pathways, including methane, serine, glyoxylate, and ethylmalonyl-CoA (EMC) metabolic pathways. While all selected organisms possessed essential genes for the serine pathway, Methylooceanibacter marginalis lacked serine hydroxymethyltransferase (SHMT), and Methylobacterium variabile exhibited both isozymes of SHMT, suggesting its potential to utilize a broader range of carbon sources. Notably, Methylobrevis sp. displayed a unique serine-glyoxylate transaminase isozyme not found in other organisms. Only nine organisms featured anaplerotic enzymes (isocitrate lyase and malate synthase) for the glyoxylate pathway, with the rest following the EMC pathway. Methylovirgula sp. 4MZ18 stood out by acquiring genes from both glyoxylate and EMC pathways, and Methylocapsa sp. S129 featured an A-form malate synthase, unlike the G-form found in the remaining organisms. Our findings also revealed distinct phylogenetic relationships and clustering patterns among type II methylotrophs, leading to the proposal of a separate genus for Methylovirgula sp. 4M-Z18 and Methylocapsa sp. S129. This pangenomic study unveils remarkable metabolic diversity, unique gene characteristics, and distinct clustering patterns of type II methylotrophs, providing valuable insights for future carbon sequestration and biotechnological applications. IMPORTANCE Methylotrophs have played a significant role in methane-based product production for many years. However, a comprehensive investigation into the diverse genetic architectures across different genera of methylotrophs has been lacking. This study fills this knowledge gap by enhancing our understanding of core hypothetical proteins and unique enzymes involved in methane oxidation, serine, glyoxylate, and ethylmalonyl-CoA pathways. These findings provide a valuable reference for researchers working with other methylotrophic species. Furthermore, this study not only unveils distinctive gene characteristics and phylogenetic relationships but also suggests a reclassification for Methylovirgula sp. 4M-Z18 and Methylocapsa sp. S129 into separate genera due to their unique attributes within their respective genus. Leveraging the synergies among various methylotrophic organisms, the scientific community can potentially optimize metabolite production, increasing the yield of desired end products and overall productivity.
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Affiliation(s)
- Dipayan Samanta
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
| | - Shailabh Rauniyar
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
| | - Priya Saxena
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
| | - Rajesh K Sani
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
- 2-Dimensional Materials for Biofilm Engineering, Science and Technology, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
- Data Driven Material Discovery Center for Bioengineering Innovation, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA
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Nwoba ST, Carere CR, Wigley K, Baronian K, Weaver L, Gostomski PA. Using RNA-Stable isotope probing to investigate methane oxidation metabolites and active microbial communities in methane oxidation coupled to denitrification. CHEMOSPHERE 2024; 357:142067. [PMID: 38643845 DOI: 10.1016/j.chemosphere.2024.142067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/26/2024] [Accepted: 04/15/2024] [Indexed: 04/23/2024]
Abstract
The active denitrifying communities performing methane oxidation coupled to denitrification (MOD) were investigated using samples from an aerobic reactor (∼20% O2 and 2% CH4) and a microaerobic reactor (2% O2, 2% CH4) undertaking denitrification. The methane oxidation metabolites excreted in the reactors were acetate, methanol, formate and acetaldehyde. Using anaerobic batch experiments supplemented with exogenously supplied 13C-labelled metabolites, the active denitrifying bacteria were identified using 16S rRNA amplicon sequencing and RNA-stable isotope probing (RNA-SIP). With the aerobic reactor (AR) samples, the maximum NO3- removal rates were 0.43 mmol g-1 d-1, 0.40 mmol g-1 d-1, 0.33 mmol g-1 d-1 and 0.10 mmol g-1 d-1 for exogenously supplied acetate, formate, acetaldehyde and methanol batch treatments respectively, while with the microaerobic reactor (MR) samples, the maximum NO3- removal rates were 0.41 mmol g-1 d-1, 0.33 mmol g-1 d-1, 0.38 mmol g-1 d-1 and 0.14 mmol g-1 d-1 for exogenously supplied acetate, formate, acetaldehyde and methanol batch treatments respectively. The RNA-SIP experiments with 13C-labelled acetate, formate, and methanol identified Methyloversatilis, and Hyphomicrobium as the active methane-driven denitrifying bacteria in the AR samples, while Pseudoxanthomonas, Hydrogenophaga and Hyphomicrobium were the active MOD bacteria in the MR samples. Collectively, all the data indicate that formate is a key cross-feeding metabolite excreted by methanotrophs and consumed by denitrifiers performing MOD.
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Affiliation(s)
- Sunday T Nwoba
- Dept. of Chemical & Process Engineering, University of Canterbury, Christchurch, New Zealand.
| | - Carlo R Carere
- Dept. of Chemical & Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Kathryn Wigley
- Dept. of Chemical & Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Kim Baronian
- Dept. of Chemical & Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Louise Weaver
- Institute of Environmental Science and Research Ltd., Christchurch, New Zealand
| | - Peter A Gostomski
- Dept. of Chemical & Process Engineering, University of Canterbury, Christchurch, New Zealand.
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Wang Y, Wang Y, Zhou K, Zhang H, Cheng M, Wang B, Yan X. Isolation of a facultative methanotroph Methylocystis iwaonis SD4 from rice rhizosphere and establishment of rapid genetic tools for it. Biotechnol Lett 2024:10.1007/s10529-024-03495-y. [PMID: 38733438 DOI: 10.1007/s10529-024-03495-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/10/2024] [Accepted: 04/21/2024] [Indexed: 05/13/2024]
Abstract
Methanotrophs of the genus Methylocystis are frequently found in rice paddies. Although more than ten facultative methanotrophs have been reported since 2005, none of these strains was isolated from paddy soil. Here, a facultative methane-oxidizing bacterium, Methylocystis iwaonis SD4, was isolated and characterized from rhizosphere samples of rice plants in Nanjing, China. This strain grew well on methane or methanol but was able to grow slowly using acetate or ethanol. Moreover, strain SD4 showed sustained growth at low concentrations of methane (100 and 500 ppmv). M. iwaonis SD4 could utilize diverse nitrogen sources, including nitrate, urea, ammonium as well as dinitrogen. Strain SD4 possessed genes encoding both the particulate methane monooxygenase and the soluble methane monooxygenase. Simple and rapid genetic manipulation methods were established for this strain, enabling vector transformation and unmarked genetic manipulation. Fast growth rate and efficient genetic tools make M. iwaonis SD4 an ideal model to study facultative methanotrophs, and the ability to grow on low concentration of methane implies its potential in methane removal.
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Affiliation(s)
- Yinghui Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Yuying Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Keyu Zhou
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Haili Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Minggen Cheng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Baozhan Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
- Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Key Lab of Organic-Based Fertilizers of China, Jiangsu Collaborative Innovation Center for Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
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Decembrino D, Cannella D. The thin line between monooxygenases and peroxygenases. P450s, UPOs, MMOs, and LPMOs: A brick to bridge fields of expertise. Biotechnol Adv 2024; 72:108321. [PMID: 38336187 DOI: 10.1016/j.biotechadv.2024.108321] [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: 10/31/2023] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Many scientific fields, although driven by similar purposes and dealing with similar technologies, often appear so isolated and far from each other that even the vocabularies to describe the very same phenomenon might differ. Concerning the vast field of biocatalysis, a special role is played by those redox enzymes that employ oxygen-based chemistry to unlock transformations otherwise possible only with metal-based catalysts. As such, greener chemical synthesis methods and environmentally-driven biotechnological approaches were enabled over the last decades by the use of several enzymes and ultimately resulted in the first industrial applications. Among what can be called today the environmental biorefinery sector, biomass transformation, greenhouse gas reduction, bio-gas/fuels production, bioremediation, as well as bulk or fine chemicals and even pharmaceuticals manufacturing are all examples of fields in which successful prototypes have been demonstrated employing redox enzymes. In this review we decided to focus on the most prominent enzymes (MMOs, LPMO, P450 and UPO) capable of overcoming the ∼100 kcal mol-1 barrier of inactivated CH bonds for the oxyfunctionalization of organic compounds. Harnessing the enormous potential that lies within these enzymes is of extreme value to develop sustainable industrial schemes and it is still deeply coveted by many within the aforementioned fields of application. Hence, the ambitious scope of this account is to bridge the current cutting-edge knowledge gathered upon each enzyme. By creating a broad comparison, scientists belonging to the different fields may find inspiration and might overcome obstacles already solved by the others. This work is organised in three major parts: a first section will be serving as an introduction to each one of the enzymes regarding their structural and activity diversity, whereas a second one will be encompassing the mechanistic aspects of their catalysis. In this regard, the machineries that lead to analogous catalytic outcomes are depicted, highlighting the major differences and similarities. Finally, a third section will be focusing on the elements that allow the oxyfunctionalization chemistry to occur by delivering redox equivalents to the enzyme by the action of diverse redox partners. Redox partners are often overlooked in comparison to the catalytic counterparts, yet they represent fundamental elements to better understand and further develop practical applications based on mono- and peroxygenases.
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Affiliation(s)
- Davide Decembrino
- Photobiocatalysis Unit - Crop Production and Biostimulation Lab (CPBL), and Biomass Transformation Lab (BTL), École Interfacultaire de Bioingénieurs, Université Libre de Bruxelles, Belgium.
| | - David Cannella
- Photobiocatalysis Unit - Crop Production and Biostimulation Lab (CPBL), and Biomass Transformation Lab (BTL), École Interfacultaire de Bioingénieurs, Université Libre de Bruxelles, Belgium.
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Liu C, Schmitz RA, Pol A, Hogendoorn C, Verhagen D, Peeters SH, van Alen TA, Cremers G, Mesman RA, Op den Camp HJM. Active coexistence of the novel gammaproteobacterial methanotroph 'Ca. Methylocalor cossyra' CH1 and verrucomicrobial methanotrophs in acidic, hot geothermal soil. Environ Microbiol 2024; 26:e16602. [PMID: 38454738 DOI: 10.1111/1462-2920.16602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/16/2024] [Indexed: 03/09/2024]
Abstract
Terrestrial geothermal ecosystems are hostile habitats, characterized by large emissions of environmentally relevant gases such as CO2 , CH4 , H2 S and H2 . These conditions provide a niche for chemolithoautotrophic microorganisms. Methanotrophs of the phylum Verrucomicrobia, which inhabit these ecosystems, can utilize these gases and grow at pH levels below 1 and temperatures up to 65°C. In contrast, methanotrophs of the phylum Proteobacteria are primarily found in various moderate environments. Previously, novel verrucomicrobial methanotrophs were detected and isolated from the geothermal soil of the Favara Grande on the island of Pantelleria, Italy. The detection of pmoA genes, specific for verrucomicrobial and proteobacterial methanotrophs in this environment, and the partially overlapping pH and temperature growth ranges of these isolates suggest that these distinct phylogenetic groups could coexist in the environment. In this report, we present the isolation and characterization of a thermophilic and acid-tolerant gammaproteobacterial methanotroph (family Methylococcaceae) from the Favara Grande. This isolate grows at pH values ranging from 3.5 to 7.0 and temperatures from 35°C to 55°C, and diazotrophic growth was demonstrated. Its genome contains genes encoding particulate and soluble methane monooxygenases, XoxF- and MxaFI-type methanol dehydrogenases, and all enzymes of the Calvin cycle. For this novel genus and species, we propose the name 'Candidatus Methylocalor cossyra' CH1.
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Affiliation(s)
- Changqing Liu
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Rob A Schmitz
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Arjan Pol
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Carmen Hogendoorn
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Daniël Verhagen
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Theo A van Alen
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Geert Cremers
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Rob A Mesman
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
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Goraj W, Pytlak A, Grządziel J, Gałązka A, Stępniewska Z, Szafranek-Nakonieczna A. Dynamics of Methane-Consuming Biomes from Wieliczka Formation: Environmental and Enrichment Studies. BIOLOGY 2023; 12:1420. [PMID: 37998019 PMCID: PMC10669130 DOI: 10.3390/biology12111420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023]
Abstract
The rocks surrounding Wieliczka salt deposits are an extreme, deep subsurface ecosystem that as we studied previously harbors many microorganisms, including methanotrophs. In the presented research bacterial community structure of the Wieliczka Salt Mine was determined as well as the methanotrophic activity of the natural microbiome. Finally, an enrichment culture of methane-consuming methanotrophs was obtained. The research material used in this study consisted of rocks surrounding salt deposits in the Wieliczka Salt Mine. DNA was extracted directly from the pristine rock material, as well as from rocks incubated in an atmosphere containing methane and mineral medium, and from a methanotrophic enrichment culture from this ecosystem. As a result, the study describes the composition of the microbiome in the rocks surrounding the salt deposits, while also explaining how biodiversity changes during the enrichment culture of the methanotrophic bacterial community. The contribution of methanotrophic bacteria ranged from 2.614% in the environmental sample to 64.696% in the bacterial culture. The methanotrophic enrichment culture was predominantly composed of methanotrophs from the genera Methylomonas (48.848%) and Methylomicrobium (15.636%) with methane oxidation rates from 3.353 ± 0.105 to 4.200 ± 0.505 µmol CH4 mL-1 day-1.
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Affiliation(s)
- Weronika Goraj
- Department of Biology and Biotechnology of Microorganisms, Faculty of Medicine, The John Paul II Catholic University of Lublin, Str. Konstantynów 1I, 20-708 Lublin, Poland;
| | - Anna Pytlak
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-280 Lublin, Poland;
| | - Jarosław Grządziel
- Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation–State Research Institute (IUNG-PIB), Czartoryskich 8, 24-100 Puławy, Poland; (J.G.); (A.G.)
| | - Anna Gałązka
- Department of Agricultural Microbiology, Institute of Soil Science and Plant Cultivation–State Research Institute (IUNG-PIB), Czartoryskich 8, 24-100 Puławy, Poland; (J.G.); (A.G.)
| | - Zofia Stępniewska
- Department of Biochemistry and Environmental Chemistry, The John Paul II Catholic University of Lublin, Konstantynów 1 I, 20-708 Lublin, Poland;
| | - Anna Szafranek-Nakonieczna
- Department of Biology and Biotechnology of Microorganisms, Faculty of Medicine, The John Paul II Catholic University of Lublin, Str. Konstantynów 1I, 20-708 Lublin, Poland;
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Thi Quynh Le H, Yeol Lee E. Methanotrophs: Metabolic versatility from utilization of methane to multi-carbon sources and perspectives on current and future applications. BIORESOURCE TECHNOLOGY 2023:129296. [PMID: 37302766 DOI: 10.1016/j.biortech.2023.129296] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 05/29/2023] [Accepted: 06/07/2023] [Indexed: 06/13/2023]
Abstract
The development of biorefineries for a sustainable bioeconomy has been driven by the concept of utilizing environmentally friendly and cost-effective renewable energy sources. Methanotrophic bacteria with a unique capacity to utilize methane as a carbon and energy source can serve as outstanding biocatalysts to develop C1 bioconversion technology. By establishing the utilization of diverse multi-carbon sources, integrated biorefinery platforms can be created for the concept of the circular bioeconomy. An understanding of physiology and metabolism could help to overcome challenges for biomanufacturing. This review summaries fundamental gaps for methane oxidation and the capability to utilize multi-carbon sources in methanotrophic bacteria. Subsequently, breakthroughs and challenges in harnessing methanotrophs as robust microbial chassis for industrial biotechnology were compiled and overviewed. Finally, capabilities to exploit the inherent advantages of methanotrophs to synthesize various target products in higher titers are proposed.
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Affiliation(s)
- Hoa Thi Quynh Le
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin 17104, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin 17104, Republic of Korea.
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Hwangbo M, Shao Y, Hatzinger PB, Chu KH. Acidophilic methanotrophs: Occurrence, diversity, and possible bioremediation applications. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023. [PMID: 37041665 DOI: 10.1111/1758-2229.13156] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Methanotrophs have been identified and isolated from acidic environments such as wetlands, acidic soils, peat bogs, and groundwater aquifers. Due to their methane (CH4 ) utilization as a carbon and energy source, acidophilic methanotrophs are important in controlling the release of atmospheric CH4 , an important greenhouse gas, from acidic wetlands and other environments. Methanotrophs have also played an important role in the biodegradation and bioremediation of a variety of pollutants including chlorinated volatile organic compounds (CVOCs) using CH4 monooxygenases via a process known as cometabolism. Under neutral pH conditions, anaerobic bioremediation via carbon source addition is a commonly used and highly effective approach to treat CVOCs in groundwater. However, complete dechlorination of CVOCs is typically inhibited at low pH. Acidophilic methanotrophs have recently been observed to degrade a range of CVOCs at pH < 5.5, suggesting that cometabolic treatment may be an option for CVOCs and other contaminants in acidic aquifers. This paper provides an overview of the occurrence, diversity, and physiological activities of methanotrophs in acidic environments and highlights the potential application of these organisms for enhancing contaminant biodegradation and bioremediation.
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Affiliation(s)
- Myung Hwangbo
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas, USA
| | - Yiru Shao
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas, USA
| | - Paul B Hatzinger
- Aptim Federal Services, LLC, 17 Princess Road, Lawrenceville, New Jersey, USA
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas, USA
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Zhu J, Li Y, Huang M, Xu D, Zhang Y, Zhou Q, Wu Z, Wang C. Restoration effects of submerged macrophytes on methane production and oxidation potential of lake sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161218. [PMID: 36584953 DOI: 10.1016/j.scitotenv.2022.161218] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
The restoration of submerged macrophytes is an important step in lake ecosystem restoration, during which artificially assisted measures have been widely used for macrophyte recolonization. Compared with natural restoration, the impact of artificially assisted methods on methane (CH4) production and oxidation of lake sediments remains unclear. Therefore, after the restoration of submerged macrophytes in some parts of West Lake (Hangzhou, China), sediment samples from West Lake were collected according to restoration methods and plant coverage. The CH4 production potential, oxidation potential, and microbial community structure in the sediment were discussed through whole-lake sample analysis and resampling verification from typical lake areas. From the analysis of the whole lake, the average daily CH4 production potential (ADP) of artificially restored lake areas (0.12 μg g-1 d-1) was significantly lower than that of the naturally restored lake areas (0.52 μg g-1 d-1). From the resampling analysis of typical lake areas, the ADP of naturally restored lake areas was 1.8 times that of artificially restored lake areas (P < 0.01). Although there was no significant difference in the CH4 oxidation potential between the two restoration methods, the presence of submerged macrophytes significantly increased the abundance of the dominant methanotroph Methylocaldum in the sediment, and the rate of increase in the abundance of the dominant methanotroph Methylosinus was significantly higher in artificially assisted restoration than in natural restoration. This study revealed that the artificially assisted restoration of submerged macrophytes reduced the potential for CH4 production and increased the abundance of dominant methanotrophs in the lake sediment, which would be beneficial for the reduction of CH4 emissions during lake ecological restoration and environmental management.
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Affiliation(s)
- Jianglong Zhu
- Faculty of Resources and Environmental Science, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China
| | - Yahua Li
- China University of Geosciences, No. 388 Lumo Road, Hongshan District, Wuhan 430074, China
| | - Minghui Huang
- China University of Geosciences, No. 388 Lumo Road, Hongshan District, Wuhan 430074, China
| | - Dong Xu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Yi Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Qiaohong Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Zhenbin Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China
| | - Chuan Wang
- Faculty of Resources and Environmental Science, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, No. 368 Youyi Avenue, Wuchang District, Wuhan 430062, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7 Donghu South Road, Wuchang District, Wuhan 430072, China.
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11
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Naizabekov S, Hyun SW, Na JG, Yoon S, Lee OK, Lee EY. Comparative genomic analysis of Methylocystis sp. MJC1 as a platform strain for polyhydroxybutyrate biosynthesis. PLoS One 2023; 18:e0284846. [PMID: 37163531 PMCID: PMC10171618 DOI: 10.1371/journal.pone.0284846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/06/2023] [Indexed: 05/12/2023] Open
Abstract
Biodegradable polyhydroxybutyrate (PHB) can be produced from methane by some type II methanotroph such as the genus Methylocystis. This study presents the comparative genomic analysis of a newly isolated methanotroph, Methylocystis sp. MJC1 as a biodegradable PHB-producing platform strain. Methylocystis sp. MJC1 accumulates up to 44.5% of PHB based on dry cell weight under nitrogen-limiting conditions. To facilitate its development as a PHB-producing platform strain, the complete genome sequence of Methylocystis sp. MJC1 was assembled, functionally annotated, and compared with genomes of other Methylocystis species. Phylogenetic analysis has shown that Methylocystis parvus to be the closest species to Methylocystis sp. MJC1. Genome functional annotation revealed that Methylocystis sp. MJC1 contains all major type II methanotroph biochemical pathways such as the serine cycle, EMC pathway, and Krebs cycle. Interestingly, Methylocystis sp. MJC1 has both particulate and soluble methane monooxygenases, which are not commonly found among Methylocystis species. In addition, this species also possesses most of the RuMP pathway reactions, a characteristic of type I methanotrophs, and all PHB biosynthetic genes. These comparative analysis would open the possibility of future practical applications such as the development of organism-specific genome-scale models and application of metabolic engineering strategies to Methylocystis sp. MJC1.
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Affiliation(s)
- Sanzhar Naizabekov
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Seung Woon Hyun
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Sukhwan Yoon
- Department of Civil & Environmental Engineering, Korea Advanced Institute of Science & Technology, Daejeon, Republic of Korea
| | - Ok Kyung Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, Yongin-si, Gyeonggi-do, Republic of Korea
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12
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Insights into the Genomic Potential of a Methylocystis sp. from Amazonian Floodplain Sediments. Microorganisms 2022; 10:microorganisms10091747. [PMID: 36144349 PMCID: PMC9506196 DOI: 10.3390/microorganisms10091747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/23/2022] [Accepted: 08/02/2022] [Indexed: 11/26/2022] Open
Abstract
Although floodplains are recognized as important sources of methane (CH4) in the Amazon basin, little is known about the role of methanotrophs in mitigating CH4 emissions in these ecosystems. Our previous data reported the genus Methylocystis as one of the most abundant methanotrophs in these floodplain sediments. However, information on the functional potential and life strategies of these organisms living under seasonal flooding is still missing. Here, we described the first metagenome-assembled genome (MAG) of a Methylocystis sp. recovered from Amazonian floodplains sediments, and we explored its functional potential and ecological traits through phylogenomic, functional annotation, and pan-genomic approaches. Both phylogenomics and pan-genomics identified the closest placement of the bin.170_fp as Methylocystis parvus. As expected for Type II methanotrophs, the Core cluster from the pan-genome comprised genes for CH4 oxidation and formaldehyde assimilation through the serine pathway. Furthermore, the complete set of genes related to nitrogen fixation is also present in the Core. Interestingly, the MAG singleton cluster revealed the presence of unique genes related to nitrogen metabolism and cell motility. The study sheds light on the genomic characteristics of a dominant, but as yet unexplored methanotroph from the Amazonian floodplains. By exploring the genomic potential related to resource utilization and motility capability, we expanded our knowledge on the niche breadth of these dominant methanotrophs in the Amazonian floodplains.
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13
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Abstract
Wetlands are the major natural source of methane, an important greenhouse gas. The sulfur and methane cycles in wetlands are linked—e.g., a strong sulfur cycle can inhibit methanogenesis. Although there has historically been a clear distinction drawn between methane and sulfur oxidizers, here, we isolated a methanotroph that also performed respiratory oxidization of sulfur compounds. We experimentally demonstrated that thiotrophy and methanotrophy are metabolically compatible, and both metabolisms could be expressed simultaneously in a single microorganism. These findings suggest that mixotrophic methane/sulfur-oxidizing bacteria are a previously overlooked component of environmental methane and sulfur cycles. This creates a framework for a better understanding of these redox cycles in natural and engineered wetlands. Natural and anthropogenic wetlands are major sources of the atmospheric greenhouse gas methane. Methane emissions from wetlands are mitigated by methanotrophic bacteria at the oxic–anoxic interface, a zone of intense redox cycling of carbon, sulfur, and nitrogen compounds. Here, we report on the isolation of an aerobic methanotrophic bacterium, ‘Methylovirgula thiovorans' strain HY1, which possesses metabolic capabilities never before found in any methanotroph. Most notably, strain HY1 is the first bacterium shown to aerobically oxidize both methane and reduced sulfur compounds for growth. Genomic and proteomic analyses showed that soluble methane monooxygenase and XoxF-type alcohol dehydrogenases are responsible for methane and methanol oxidation, respectively. Various pathways for respiratory sulfur oxidation were present, including the Sox–rDsr pathway and the S4I system. Strain HY1 employed the Calvin–Benson–Bassham cycle for CO2 fixation during chemolithoautotrophic growth on reduced sulfur compounds. Proteomic and microrespirometry analyses showed that the metabolic pathways for methane and thiosulfate oxidation were induced in the presence of the respective substrates. Methane and thiosulfate could therefore be independently or simultaneously oxidized. The discovery of this versatile bacterium demonstrates that methanotrophy and thiotrophy are compatible in a single microorganism and underpins the intimate interactions of methane and sulfur cycles in oxic–anoxic interface environments.
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14
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Identification of active gaseous-alkane degraders at natural gas seeps. THE ISME JOURNAL 2022; 16:1705-1716. [PMID: 35319019 PMCID: PMC9213486 DOI: 10.1038/s41396-022-01211-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/30/2022] [Accepted: 02/04/2022] [Indexed: 11/29/2022]
Abstract
Natural gas seeps release significant amounts of methane and other gases including ethane and propane contributing to global climate change. In this study, bacterial actively consuming short-chain alkanes were identified by cultivation, whole-genome sequencing, and stable-isotope probing (SIP)-metagenomics using 13C-propane and 13C-ethane from two different natural gas seeps, Pipe Creek and Andreiasu Everlasting Fire. Nearly 100 metagenome-assembled genomes (MAGs) (completeness 70–99%) were recovered from both sites. Among these, 16 MAGs had genes encoding the soluble di-iron monooxygenase (SDIMO). The MAGs were affiliated to Actinobacteria (two MAGs), Alphaproteobacteria (ten MAGs), and Gammaproteobacteria (four MAGs). Additionally, three gaseous-alkane degraders were isolated in pure culture, all of which could grow on ethane, propane, and butane and possessed SDIMO-related genes. Two Rhodoblastus strains (PC2 and PC3) were from Pipe Creek and a Mycolicibacterium strain (ANDR5) from Andreiasu. Strains PC2 and PC3 encoded putative butane monooxygenases (MOs) and strain ANDR5 contained a propane MO. Mycolicibacterium strain ANDR5 and MAG19a, highly abundant in incubations with 13C-ethane, share an amino acid identity (AAI) of 99.3%. We show using a combination of enrichment and isolation, and cultivation-independent techniques, that these natural gas seeps contain a diverse community of active bacteria oxidising gaseous-alkanes, which play an important role in biogeochemical cycling of natural gas.
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15
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Cai Y, Yun J, Jia Z. Phylogeny and Metabolic Potential of the Methanotrophic Lineage MO3 in Beijerinckiaceae from the Paddy Soil through Metagenome-Assembled Genome Reconstruction. Microorganisms 2022; 10:microorganisms10050955. [PMID: 35630399 PMCID: PMC9145241 DOI: 10.3390/microorganisms10050955] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/22/2022] [Accepted: 04/29/2022] [Indexed: 01/27/2023] Open
Abstract
Although the study of aerobic methane-oxidizing bacteria (MOB, methanotrophs) has been carried out for more than a hundred years, there are many uncultivated methanotrophic lineages whose metabolism is largely unknown. Here, we reconstructed a nearly complete genome of a Beijerinckiaceae methanotroph from the enrichment of paddy soil by using nitrogen-free M2 medium. The methanotroph labeled as MO3_YZ.1 had a size of 3.83 Mb, GC content of 65.6%, and 3442 gene-coding regions. Based on phylogeny of pmoA gene and genome and the genomic average nucleotide identity, we confirmed its affiliation to the MO3 lineage and a close relationship to Methylocapsa. MO3_YZ.1 contained mxaF- and xoxF-type methanol dehydrogenase. MO3_YZ.1 used the serine cycle to assimilate carbon and regenerated glyoxylate through the glyoxylate shunt as it contained isocitrate lyase and complete tricarboxylic acid cycle-coding genes. The ethylmalonyl-CoA pathway and Calvin–Benson–Bassham cycle were incomplete in MO3_YZ.1. Three acetate utilization enzyme-coding genes were identified, suggesting its potential ability to utilize acetate. The presence of genes for N2 fixation, sulfur transformation, and poly-β-hydroxybutyrate synthesis enable its survival in heterogeneous habitats with fluctuating supplies of carbon, nitrogen, and sulfur.
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Affiliation(s)
- Yuanfeng Cai
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Correspondence: (Y.C.); (Z.J.); Tel.: +86-25-8688-1850 (Y.C.); +86-25-8688-1311 (Z.J.)
| | - Juanli Yun
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China;
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Correspondence: (Y.C.); (Z.J.); Tel.: +86-25-8688-1850 (Y.C.); +86-25-8688-1311 (Z.J.)
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16
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Zill D, Lettau E, Lorent C, Seifert F, Singh P, Lauterbach L. Crucial role of the chaperonin GroES/EL for heterologous production of the soluble methane monooxygenase from Methylomonas methanica MC09. Chembiochem 2022; 23:e202200195. [PMID: 35385600 PMCID: PMC9324122 DOI: 10.1002/cbic.202200195] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Indexed: 11/15/2022]
Abstract
Methane is a widespread energy source and can serve as an attractive C1 building block for a future bioeconomy. The soluble methane monooxygenase (sMMO) is able to break the strong C−H bond of methane and convert it to methanol. The high structural complexity, multiplex cofactors, and unfamiliar folding or maturation procedures of sMMO have hampered the heterologous production and thus biotechnological applications. Here, we demonstrate the heterologous production of active sMMO from the marine Methylomonas methanica MC09 in Escherichia coli by co‐synthesizing the GroES/EL chaperonin. Iron determination, electron paramagnetic resonance spectroscopy, and native gel immunoblots revealed the incorporation of the non‐heme diiron centre and homodimer formation of active sMMO. The production of recombinant sMMO will enable the expansion of the possibilities of detailed studies, allowing for a variety of novel biotechnological applications.
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Affiliation(s)
- Domenic Zill
- RWTH Aachen Fakultät für Mathematik Informatik und Naturwissenschaften: Rheinisch Westfalische Technische Hochschule Aachen Fakultat fur Mathematik Informatik und Naturwissenschaften, Institute of Applied Microbiology, GERMANY
| | - Elisabeth Lettau
- RWTH Aachen Faculty of Mathematics Computer Science and Natural Sciences: Rheinisch Westfalische Technische Hochschule Aachen Fakultat fur Mathematik Informatik und Naturwissenschaften, Institute of Applied Microbiology, GERMANY
| | - Christian Lorent
- TU Berlin: Technische Universitat Berlin, Institute for Chemistry, GERMANY
| | - Franziska Seifert
- Martin-Luther-Universität Halle-Wittenberg: Martin-Luther-Universitat Halle-Wittenberg, Institut für Pharmazeutische Technologie und Biopharmazie, GERMANY
| | - Praveen Singh
- RWTH Aachen Faculty of Mathematics Computer Science and Natural Sciences: Rheinisch Westfalische Technische Hochschule Aachen Fakultat fur Mathematik Informatik und Naturwissenschaften, Institute of Applied Microbiology, GERMANY
| | - Lars Lauterbach
- RWTH Aachen University: Rheinisch-Westfalische Technische Hochschule Aachen, Institute of Applied Microbiology, Worringer Weg 1, 52074, Aachen, GERMANY
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17
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Crombie AT. The effect of lanthanum on growth and gene expression in a facultative methanotroph. Environ Microbiol 2021; 24:596-613. [PMID: 34320271 PMCID: PMC9291206 DOI: 10.1111/1462-2920.15685] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 07/25/2021] [Indexed: 11/29/2022]
Abstract
The biological importance of lanthanides has only recently been identified, initially as the active site metal of the alternative methanol dehydrogenase (MDH) Xox‐MDH. So far, the effect of lanthanide (Ln) has only been studied in relatively few organisms. This work investigated the effects of Ln on gene transcription and protein expression in the facultative methanotroph Methylocella silvestris BL2, a widely distributed methane‐oxidizing bacterium with the unique ability to grow not just on methane but also on other typical components of natural gas, ethane and propane. Expression of calcium‐ or Ln‐dependent MDH was controlled by Ln (the lanthanide switch) during growth on one‐, two‐ or three‐carbon substrates, and Ln imparted a considerable advantage during growth on propane, a novel result extending the importance of Ln to consumers of this component of natural gas. Two Xox‐MDHs were expressed and regulated by Ln in M. silvestris, but interestingly Ln repressed rather than induced expression of the second Xox‐MDH. Despite the metabolic versatility of M. silvestris, no other alcohol dehydrogenases were expressed, and in double‐mutant strains lacking genes encoding both Ca‐ and Ln‐dependent MDHs (mxaF and xoxF5 or xoxF1), growth on methanol and ethanol appeared to be enabled by expression of the soluble methane monooxygenase.
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Affiliation(s)
- Andrew T Crombie
- School of Biological Science, University of East Anglia, Norwich, NR4 7TJ, UK.,School of Environmental Science, University of East Anglia, Norwich, NR4 7TJ, UK
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18
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Guerrero-Cruz S, Vaksmaa A, Horn MA, Niemann H, Pijuan M, Ho A. Methanotrophs: Discoveries, Environmental Relevance, and a Perspective on Current and Future Applications. Front Microbiol 2021; 12:678057. [PMID: 34054786 PMCID: PMC8163242 DOI: 10.3389/fmicb.2021.678057] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
Methane is the final product of the anaerobic decomposition of organic matter. The conversion of organic matter to methane (methanogenesis) as a mechanism for energy conservation is exclusively attributed to the archaeal domain. Methane is oxidized by methanotrophic microorganisms using oxygen or alternative terminal electron acceptors. Aerobic methanotrophic bacteria belong to the phyla Proteobacteria and Verrucomicrobia, while anaerobic methane oxidation is also mediated by more recently discovered anaerobic methanotrophs with representatives in both the bacteria and the archaea domains. The anaerobic oxidation of methane is coupled to the reduction of nitrate, nitrite, iron, manganese, sulfate, and organic electron acceptors (e.g., humic substances) as terminal electron acceptors. This review highlights the relevance of methanotrophy in natural and anthropogenically influenced ecosystems, emphasizing the environmental conditions, distribution, function, co-existence, interactions, and the availability of electron acceptors that likely play a key role in regulating their function. A systematic overview of key aspects of ecology, physiology, metabolism, and genomics is crucial to understand the contribution of methanotrophs in the mitigation of methane efflux to the atmosphere. We give significance to the processes under microaerophilic and anaerobic conditions for both aerobic and anaerobic methane oxidizers. In the context of anthropogenically influenced ecosystems, we emphasize the current and potential future applications of methanotrophs from two different angles, namely methane mitigation in wastewater treatment through the application of anaerobic methanotrophs, and the biotechnological applications of aerobic methanotrophs in resource recovery from methane waste streams. Finally, we identify knowledge gaps that may lead to opportunities to harness further the biotechnological benefits of methanotrophs in methane mitigation and for the production of valuable bioproducts enabling a bio-based and circular economy.
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Affiliation(s)
- Simon Guerrero-Cruz
- Catalan Institute for Water Research (ICRA), Girona, Spain
- Universitat de Girona, Girona, Spain
| | - Annika Vaksmaa
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, ’t Horntje, Netherlands
| | - Marcus A. Horn
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
| | - Helge Niemann
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, ’t Horntje, Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
- Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT the Arctic University of Norway, Tromsø, Norway
| | - Maite Pijuan
- Catalan Institute for Water Research (ICRA), Girona, Spain
- Universitat de Girona, Girona, Spain
| | - Adrian Ho
- Institute of Microbiology, Leibniz Universität Hannover, Hannover, Germany
- Division of Applied Life Sciences, Gyeongsang National University, Jinju, South Korea
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19
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Gontijo JB, Paula FS, Venturini AM, Yoshiura CA, Borges CD, Moura JMS, Bohannan BJM, Nüsslein K, Rodrigues JLM, Tsai SM. Not just a methane source: Amazonian floodplain sediments harbour a high diversity of methanotrophs with different metabolic capabilities. Mol Ecol 2021; 30:2560-2572. [PMID: 33817881 DOI: 10.1111/mec.15912] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 03/22/2021] [Accepted: 03/26/2021] [Indexed: 01/03/2023]
Abstract
The Amazonian floodplain forests are dynamic ecosystems of great importance for the regional hydrological and biogeochemical cycles and function as a significant CH4 source contributing to the global carbon balance. Unique geochemical factors may drive the microbial community composition and, consequently, affect CH4 emissions across floodplain areas. Here, we report the in situ composition of CH4 cycling microbial communities in Amazonian floodplain sediments. We considered how abiotic factors may affect the microbial community composition and, more specifically, CH4 cycling groups. We collected sediment samples during wet and dry seasons from three different types of floodplain forests, along with upland forest soil samples, from the Eastern Amazon, Brazil. We used high-resolution sequencing of archaeal and bacterial 16S rRNA genes combined with real-time PCR to quantify Archaea and Bacteria, as well as key functional genes indicative of the presence of methanogenic (mcrA) and methanotrophic (pmoA) microorganisms. Methanogens were found to be present in high abundance in floodplain sediments, and they seem to resist the dramatic environmental changes between flooded and nonflooded conditions. Methanotrophs known to use different pathways to oxidise CH4 were detected, including anaerobic archaeal and bacterial taxa, indicating that a wide metabolic diversity may be harboured in this highly variable environment. The floodplain environmental variability, which is affected by the river origin, drives not only the sediment chemistry but also the composition of the microbial communities. These environmental changes seem also to affect the pools of methanotrophs occupying distinct niches. Understanding these shifts in the methanotrophic communities could improve our comprehension of the CH4 emissions in the region.
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Affiliation(s)
- Júlia B Gontijo
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Fabiana S Paula
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil.,Department of Biological Oceanography, Oceanographic Institute, University of São Paulo, São Paulo, Brazil
| | - Andressa M Venturini
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Caio A Yoshiura
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Clovis D Borges
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
| | - José Mauro S Moura
- Center for Interdisciplinary Formation, Federal University of Western Pará, Santarém, Brazil
| | - Brendan J M Bohannan
- Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
| | - Klaus Nüsslein
- Department of Microbiology, University of Massachusetts, Amherst, MA, USA
| | - Jorge L Mazza Rodrigues
- Department of Land, Air and Water Resources, University of California, Davis, CA, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Siu M Tsai
- Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil
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