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Qiu Y, Zhang J, Tong YW, He Y. Reverse electron transfer: Novel anaerobic methanogenesis pathway regulated through exogenous CO 2 synergized with biochar. BIORESOURCE TECHNOLOGY 2024; 401:130741. [PMID: 38670292 DOI: 10.1016/j.biortech.2024.130741] [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: 02/03/2024] [Revised: 03/25/2024] [Accepted: 04/24/2024] [Indexed: 04/28/2024]
Abstract
Acid accumulation and carbon emission are two major challenges in anaerobic digestion. Syntrophic consortia can employ reverse electron transfer (RET) to facilitate thermodynamically unfavorable redox reactions during acetogenesis. However, the potential mechanisms and regulatory methods of RET remain unclear. This study examines the regulatory mechanisms by which exogenous CO2 affects RET and demonstrates that biochar maximizes CO2 solubility at 25.8 mmol/L to enhance effects further. CO2 synergized with biochar significantly increases cumulative methane production and propionate degradation rate. From the bioenergetic perspective, CO2 decreases energy level to a maximum of -87 kJ/mol, strengthening the thermodynamic viability. The underlying mechanism can be attributed to RET promotion, as indicated by increased formate dehydrogenase and enrichment of H2/formate-producing bacteria with their partner Methanospirillum hungatei. Moreover, the 5 % 13CH4 and methane contribution result show that CO2 accomplishes directed methanogenesis. Overall, this investigation riches the roles of CO2 and biochar in AD surrounding RET.
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Affiliation(s)
- Yang Qiu
- China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingxin Zhang
- China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 200240, China; School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Energy and Environmental Sustainability Solutions for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore, 138602, Singapore.
| | - Yen Wah Tong
- Department of Chemical & Biomolecular Engineering, National University of Singapore, Singapore; Energy and Environmental Sustainability Solutions for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 CREATE Way, Singapore, 138602, Singapore
| | - Yiliang He
- China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 200240, China; School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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2
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Conrad R. Complexity of temperature dependence in methanogenic microbial environments. Front Microbiol 2023; 14:1232946. [PMID: 37485527 PMCID: PMC10359720 DOI: 10.3389/fmicb.2023.1232946] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/20/2023] [Indexed: 07/25/2023] Open
Abstract
There is virtually no environmental process that is not dependent on temperature. This includes the microbial processes that result in the production of CH4, an important greenhouse gas. Microbial CH4 production is the result of a combination of many different microorganisms and microbial processes, which together achieve the mineralization of organic matter to CO2 and CH4. Temperature dependence applies to each individual step and each individual microbe. This review will discuss the different aspects of temperature dependence including temperature affecting the kinetics and thermodynamics of the various microbial processes, affecting the pathways of organic matter degradation and CH4 production, and affecting the composition of the microbial communities involved. For example, it was found that increasing temperature results in a change of the methanogenic pathway with increasing contribution from mainly acetate to mainly H2/CO2 as immediate CH4 precursor, and with replacement of aceticlastic methanogenic archaea by thermophilic syntrophic acetate-oxidizing bacteria plus thermophilic hydrogenotrophic methanogenic archaea. This shift is consistent with reaction energetics, but it is not obligatory, since high temperature environments exist in which acetate is consumed by thermophilic aceticlastic archaea. Many studies have shown that CH4 production rates increase with temperature displaying a temperature optimum and a characteristic apparent activation energy (Ea). Interestingly, CH4 release from defined microbial cultures, from environmental samples and from wetland field sites all show similar Ea values around 100 kJ mol-1 indicating that CH4 production rates are limited by the methanogenic archaea rather than by hydrolysis of organic matter. Hence, the final rather than the initial step controls the methanogenic degradation of organic matter, which apparently is rarely in steady state.
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Imaura Y, Okamoto S, Hino T, Ogami Y, Katayama YA, Tanimura A, Inoue M, Kamikawa R, Yoshida T, Sako Y. Isolation, Genomic Sequence and Physiological Characterization of Parageobacillus sp. G301, an Isolate Capable of Both Hydrogenogenic and Aerobic Carbon Monoxide Oxidation. Appl Environ Microbiol 2023; 89:e0018523. [PMID: 37219438 PMCID: PMC10304674 DOI: 10.1128/aem.00185-23] [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: 02/16/2023] [Accepted: 05/06/2023] [Indexed: 05/24/2023] Open
Abstract
Prokaryotes that can oxidize carbon monoxide (CO oxidizers) can use this gas as a source of carbon or energy. They oxidize carbon monoxide with carbon monoxide dehydrogenases (CODHs): these are divided into nickel-containing CODH (Ni-CODH), which are sensitive to O2, and molybdenum-containing CODH (Mo-CODH), which can function aerobically. The oxygen conditions required for CO oxidizers to oxidize CO may be limited, as those which have been isolated and characterized so far contain either Ni- or Mo-CODH. Here, we report a novel CO oxidizer, Parageobacillus sp. G301, which is capable of CO oxidation using both types of CODH based on genomic and physiological characterization. This thermophilic, facultatively anaerobic Bacillota bacterium was isolated from the sediments of a freshwater lake. Genomic analyses revealed that strain G301 possessed both Ni-CODH and Mo-CODH. Genome-based reconstruction of its respiratory machinery and physiological investigations indicated that CO oxidation by Ni-CODH was coupled with H2 production (proton reduction), whereas CO oxidation by Mo-CODH was coupled with O2 reduction under aerobic conditions and nitrate reduction under anaerobic conditions. G301 would thus be able to thrive via CO oxidation under a wide range of conditions, from aerobic environments to anaerobic environments, even with no terminal electron acceptors other than protons. Comparative genome analyses revealed no significant differences in genome structures and encoded cellular functions, except for CO oxidation between CO oxidizers and non-CO oxidizers in the genus Parageobacillus; CO oxidation genes are retained exclusively for CO metabolism and related respiration. IMPORTANCE Microbial CO oxidation has received much attention because it contributes to global carbon cycling in addition to functioning as a remover of CO, which is toxic to many organisms. Some microbial CO oxidizers, including both bacteria and archaea, exhibit sister relationships with non-CO oxidizers even in genus-level monophyletic groups. In this study, we demonstrated that a new isolate, Parageobacillus sp. G301, is capable of both anaerobic (hydrogenogenic) and aerobic CO oxidation, which has not been previously reported. The discovery of this new isolate, which is versatile in CO metabolism, will accelerate research on CO oxidizers with diverse CO metabolisms, expanding our understanding of microbial diversity. Through comparative genomic analyses, we propose that CO oxidation genes are not essential genetic elements in the genus Parageobacillus, providing insights into the factors which shape the punctate distribution of CO oxidizers in the prokaryote tree, even in genus-level monophyletic groups.
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Affiliation(s)
| | | | - Taiki Hino
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yusuke Ogami
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | - Ayumi Tanimura
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masao Inoue
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- R-GIRO, Ritsumeikan University, Kusatsu, Shiga, Japan
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Ryoma Kamikawa
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takashi Yoshida
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoshihiko Sako
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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Song T, Liu Y, Kolton M, Wilson RM, Keller JK, Rolando JL, Chanton JP, Kostka JE. Porewater constituents inhibit microbially mediated greenhouse gas production (GHG) and regulate the response of soil organic matter decomposition to warming in anoxic peat from a Sphagnum-dominated bog. FEMS Microbiol Ecol 2023; 99:fiad060. [PMID: 37280172 DOI: 10.1093/femsec/fiad060] [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: 09/25/2022] [Revised: 05/16/2023] [Accepted: 06/05/2023] [Indexed: 06/08/2023] Open
Abstract
Northern peatlands store approximately one-third of terrestrial soil carbon. Climate warming is expected to stimulate the microbially mediated degradation of peat soil organic matter (SOM), leading to increasing greenhouse gas (GHG; carbon dioxide, CO2; methane, CH4) production and emission. Porewater dissolved organic matter (DOM) plays a key role in SOM decomposition; however, the mechanisms controlling SOM decomposition and its response to warming remain unclear. The temperature dependence of GHG production and microbial community dynamics were investigated in anoxic peat from a Sphagnum-dominated peatland. In this study, peat decomposition, which was quantified by GHG production and carbon substrate utilization is limited by terminal electron acceptors (TEA) and DOM, and these controls of microbially mediated SOM degradation are temperature-dependent. Elevated temperature led to a slight decrease in microbial diversity, and stimulated the growth of specific methanotrophic and syntrophic taxa. These results confirm that DOM is a major driver of decomposition in peatland soils contains inhibitory compounds, but the inhibitory effect is alleviated by warming.
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Affiliation(s)
- Tianze Song
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Yutong Liu
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States
- Department of Civil & Environmental Engineering, Pennsylvania State University, University Park, University Park, PA 16802, United States
| | - Max Kolton
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States
- French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion, University of the Negev, Beer Sheva, 8499000, Israel
| | - Rachel M Wilson
- Department of Earth, Ocean & Atmospheric Science, Florida State University, Tallahassee, FL 32304, United States
| | - Jason K Keller
- Schmid College of Science and Technology, Chapman University, 1 University Dr, Orange, CA 92866, United States
| | - Jose L Rolando
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Jeffrey P Chanton
- Department of Earth, Ocean & Atmospheric Science, Florida State University, Tallahassee, FL 32304, United States
| | - Joel E Kostka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30318, United States
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA 30332, United States
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5
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Shi LD, Zhou YJ, Tang XJ, Kappler A, Chistoserdova L, Zhu LZ, Zhao HP. Coupled Aerobic Methane Oxidation and Arsenate Reduction Contributes to Soil-Arsenic Mobilization in Agricultural Fields. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11845-11856. [PMID: 35920083 DOI: 10.1021/acs.est.2c01878] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microbial oxidation of organic compounds can promote arsenic release by reducing soil-associated arsenate to the more mobile form arsenite. While anaerobic oxidation of methane has been demonstrated to reduce arsenate, it remains elusive whether and to what extent aerobic methane oxidation (aeMO) can contribute to reductive arsenic mobilization. To fill this knowledge gap, we performed incubations of both microbial laboratory cultures and soil samples from arsenic-contaminated agricultural fields in China. Incubations with laboratory cultures showed that aeMO could couple to arsenate reduction, wherein the former bioprocess was carried out by aerobic methanotrophs and the latter by a non-methanotrophic bacterium belonging to a novel and uncultivated representative of Burkholderiaceae. Metagenomic analyses combined with metabolite measurements suggested that formate served as the interspecies electron carrier linking aeMO to arsenate reduction. Such coupled bioprocesses also take place in the real world, supported by a similar stoichiometry and gene activity in the incubations with natural paddy soils, and contribute up to 76.2% of soil-arsenic mobilization into pore waters in the top layer of the soils where oxygen was present. Overall, this study reveals a previously overlooked yet significant contribution of aeMO to reductive arsenic mobilization.
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Affiliation(s)
- Ling-Dong Shi
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yu-Jie Zhou
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xian-Jin Tang
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Andreas Kappler
- Center for Applied Geosciences, University of Tübingen, Tübingen 72074, Germany
| | - Ludmila Chistoserdova
- Department of Chemical Engineering, University of Washington, Seattle, Washington 98195-0005, United States
| | - Li-Zhong Zhu
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - He-Ping Zhao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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Pierangeli GMF, Domingues MR, Choueri RB, Hanisch WS, Gregoracci GB, Benassi RF. Spatial Variation and Environmental Parameters Affecting the Abundant and Rare Communities of Bacteria and Archaea in the Sediments of Tropical Urban Reservoirs. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02047-z. [PMID: 35610383 DOI: 10.1007/s00248-022-02047-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Microbial communities in freshwater sediments play an important role in organic matter remineralization, contributing to biogeochemical cycles, nutrient release, and greenhouse gases emissions. Bacterial and archaeal communities might show spatial or seasonal patterns and were shown to be influenced by distinct environmental parameters and anthropogenic activities, including pollution and damming. Here, we determined the spatial variation and the environmental variables influencing the abundant and rare bacterial and archaeal communities in the sediments of eutrophic-hypereutrophic reservoirs from a tropical urban area in Brazil. The most abundant microbes included mainly Anaerolineae and Deltaproteobacteria genera from the Bacteria domain, and Methanomicrobia genera from the Archaea domain. Microbial communities differed spatially in each reservoir, reflecting the establishment of specific environmental conditions. Locations with better or worst water quality, or close to a dam, showed more distinct microbial communities. Besides the water column depth, microbial communities were affected by some pollution indicators, including total phosphorus, orthophosphate, electrical conductivity, and biochemical oxygen demand. Distinct proportions of variation were explained by spatial and environmental parameters for each microbial community. Furthermore, spatial variations in environmental parameters affecting these communities, especially the most distinct ones, contributed to microbial variations mediated by spatial and environmental properties together. Finally, our study showed that different pressures in each reservoir affected the sediment microbiota, promoting different responses and possible adaptations of abundant and rare bacterial and archaeal communities.
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Affiliation(s)
- Gabrielle Maria Fonseca Pierangeli
- Marine Biotechnology Lab (Room 505), Institute of Marine Sciences, Federal University of São Paulo, Campus Baixada Santista, Rua Dr. Carvalho de Mendonça, 144 - Vila Belmiro, Santos, SP, 11070-100, Brazil
| | - Mercia Regina Domingues
- Center of Engineering, Modeling and Applied Social Sciences, Federal University of ABC, Santo André, SP, Brazil
| | - Rodrigo Brasil Choueri
- Marine Biotechnology Lab (Room 505), Institute of Marine Sciences, Federal University of São Paulo, Campus Baixada Santista, Rua Dr. Carvalho de Mendonça, 144 - Vila Belmiro, Santos, SP, 11070-100, Brazil
| | | | - Gustavo Bueno Gregoracci
- Marine Biotechnology Lab (Room 505), Institute of Marine Sciences, Federal University of São Paulo, Campus Baixada Santista, Rua Dr. Carvalho de Mendonça, 144 - Vila Belmiro, Santos, SP, 11070-100, Brazil.
| | - Roseli Frederigi Benassi
- Center of Engineering, Modeling and Applied Social Sciences, Federal University of ABC, Santo André, SP, Brazil
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7
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Orsi WD, Schink B, Buckel W, Martin WF. Physiological limits to life in anoxic subseafloor sediment. FEMS Microbiol Rev 2020; 44:219-231. [PMID: 32065239 PMCID: PMC7269680 DOI: 10.1093/femsre/fuaa004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/13/2020] [Indexed: 12/21/2022] Open
Abstract
In subseafloor sediment, microbial cell densities exponentially decrease with depth into the fermentation zone. Here, we address the classical question of 'why are cells dying faster than they are growing?' from the standpoint of physiology. The stoichiometries of fermentative ATP production and consumption in the fermentation zone place bounds on the conversion of old cell biomass into new. Most fermentable organic matter in deep subseafloor sediment is amino acids from dead cells because cells are mostly protein by weight. Conversion of carbon from fermented dead cell protein into methanogen protein via hydrogenotrophic and acetoclastic methanogenesis occurs at ratios of ∼200:1 and 100:1, respectively, while fermenters can reach conversion ratios approaching 6:1. Amino acid fermentations become thermodynamically more efficient at lower substrate and product concentrations, but the conversion of carbon from dead cell protein into fermenter protein is low because of the high energetic cost of translation. Low carbon conversion factors within subseafloor anaerobic feeding chains account for exponential declines in cellular biomass in the fermentation zone of anoxic sediments. Our analysis points to the existence of a life-death transition zone in which the last biologically catalyzed life processes are replaced with purely chemical reactions no longer coupled to life.
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Affiliation(s)
- William D Orsi
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - Bernhard Schink
- Department of Biology, University of Konstanz, 78457 Constance, Germany
| | - Wolfgang Buckel
- Department of Biology, Philipps-Universität, 35032 Marburg, Germany
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine Universität Düsseldorf, 40225 Düsseldorf, Germany
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8
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Al-Fathi H, Koch M, Lorenz WG, Lechner U. Anaerobic degradation of 2,4,5-trichlorophenoxyacetic acid by enrichment cultures from freshwater sediments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:34459-34467. [PMID: 31642015 DOI: 10.1007/s11356-019-06584-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
The anaerobic biodegradation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was investigated using enrichment cultures from freshwater sediments at two different sites in the region of Halle, central Germany. 2,4,5-T and different organic acids or hydrogen were added as possible electron acceptor and electron donors, respectively. The primary enrichment cultures from Saale river sediment completely degraded 2,4,5-T to 3-chlorophenol (3-CP) (major product) and 3,4-dichlorophenol (3,4-DCP) during a 28-day incubation period. Subcultures showed ether cleavage of 2,4,5-T to 2,4,5-trichlorophenol and its stoichiometric dechlorination to 3-CP only in the presence of butyrate. In contrast, the primary enrichment culture from sediment of Posthorn pond dechlorinated 2,4,5-T to 2,5-dichlorophenoxyacetic acid (2,5-D), which, in the presence of butyrate, was degraded further to products such as 3,4-DCP, 2,5-DCP, and 3CP, indicating ether cleaving activities and subsequent dechlorination steps. Experiments with pure cultures of Dehalococcoides mccartyi and Desulfitobacterium hafniense demonstrated their specific dechlorination steps within the overall 2,4,5-T degradation pathways. The results indicate that the route and efficiency of anaerobic 2,4,5-T degradation in the environment depend heavily on the microorganisms present and the availability of slowly fermentable organic compounds.
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Affiliation(s)
- Hassan Al-Fathi
- Institute of Biology/Microbiology, Martin-Luther University Halle-Wittenberg, Halle, Germany
- Department Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Mandy Koch
- Institute of Chemistry/Food and Environmental Chemistry, Martin-Luther University Halle-Wittenberg, Halle, Germany
| | - Wilhelm G Lorenz
- Institute of Chemistry/Food and Environmental Chemistry, Martin-Luther University Halle-Wittenberg, Halle, Germany
| | - Ute Lechner
- Institute of Biology/Microbiology, Martin-Luther University Halle-Wittenberg, Halle, Germany.
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Schoelmerich MC, Müller V. Energy-converting hydrogenases: the link between H 2 metabolism and energy conservation. Cell Mol Life Sci 2019; 77:1461-1481. [PMID: 31630229 DOI: 10.1007/s00018-019-03329-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/17/2019] [Accepted: 10/01/2019] [Indexed: 10/25/2022]
Abstract
The reversible interconversion of molecular hydrogen and protons is one of the most ancient microbial metabolic reactions and catalyzed by hydrogenases. A widespread yet largely enigmatic group comprises multisubunit [NiFe] hydrogenases, that directly couple H2 metabolism to the electrochemical ion gradient across the membranes of bacteria and of archaea. These complexes are collectively referred to as energy-converting hydrogenases (Ech), as they reversibly transform redox energy into physicochemical energy. Redox energy is typically provided by a low potential electron donor such as reduced ferredoxin to fuel H2 evolution and the establishment of a transmembrane electrochemical ion gradient ([Formula: see text]). The [Formula: see text] is then utilized by an ATP synthase for energy conservation by generating ATP. This review describes the modular structure/function of Ech complexes, focuses on insights into the energy-converting mechanisms, describes the evolutionary context and delves into the implications of relying on an Ech complex as respiratory enzyme for microbial metabolism.
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Affiliation(s)
- Marie Charlotte Schoelmerich
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.,Microbiology and Biotechnology, Institute of Plant Sciences and Microbiology, Universität Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany
| | - Volker Müller
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt, Germany.
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Xia X, Zhang J, Song T, Lu Y. Stimulation of Smithella-dominating propionate oxidation in a sediment enrichment by magnetite and carbon nanotubes. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:236-248. [PMID: 30790444 DOI: 10.1111/1758-2229.12737] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
Recent studies have shown that application of conductive materials including magnetite and carbon nanotubes (CNTs) can promote the methanogenic decomposition of short-chain fatty acids and even more complex organic matter in anaerobic digesters and natural habitats. The linkage to microbial identity and the mechanisms, however, remain poorly understood. Here, we evaluate the effects of nanoscale magnetite (nanoFe3 O4 ) and multiwalled CNTs on the syntrophic oxidation of propionate in an enrichment obtained from lake sediment. The microbial populations were composed mainly of Smithella, Syntrophomonas, Methanosaeta, Methanosarcina and Methanoregula. In addition to acetate, butyrate was transiently accumulated indicating that propionate was oxidized by Smithella via the dismutation pathway and part of the leaked butyrate was oxidized by Syntrophomonas. Propionate oxidation and CH4 production were significantly accelerated in the presence of nanoFe3 O4 and CNTs. While propionate oxidation was suppressed upon H2 application and suspended completely upon formate application in the control, this suppressive effect was substantially compromised in the presence of nanoFe3 O4 and CNTs. The tests on hydrogenotrophic methanogenesis of a pure culture methanogen and of the enrichment culture without propionate showed negative effect by both materials. The positive effect of nanoFe3 O4 disappeared when it was insulated by surface-coating with silica. Observations made with fluorescence in situ hybridization and scanning electron microscope indicated the extensive formation of microbial cell-conductive material mixture aggregates. Our results suggest that direct interspecies electron transfer is likely activated by the conductive materials and operates in concert with H2 /formate-dependent electron transfer for syntrophic propionate oxidation in the sediment enrichment.
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Affiliation(s)
- Xingxuan Xia
- Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Jianchao Zhang
- Institute of Surface-Earth System Science, Tianjin University, 300072, China
| | - Tianze Song
- Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yahai Lu
- Urban and Environmental Sciences, Peking University, Beijing, 100871, China
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11
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Schuchmann K, Chowdhury NP, Müller V. Complex Multimeric [FeFe] Hydrogenases: Biochemistry, Physiology and New Opportunities for the Hydrogen Economy. Front Microbiol 2018; 9:2911. [PMID: 30564206 PMCID: PMC6288185 DOI: 10.3389/fmicb.2018.02911] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/13/2018] [Indexed: 12/03/2022] Open
Abstract
Hydrogenases are key enzymes of the energy metabolism of many microorganisms. Especially in anoxic habitats where molecular hydrogen (H2) is an important intermediate, these enzymes are used to expel excess reducing power by reducing protons or they are used for the oxidation of H2 as energy and electron source. Despite the fact that hydrogenases catalyze the simplest chemical reaction of reducing two protons with two electrons it turned out that they are often parts of multimeric enzyme complexes catalyzing complex chemical reactions with a multitude of functions in the metabolism. Recent findings revealed multimeric hydrogenases with so far unknown functions particularly in bacteria from the class Clostridia. The discovery of [FeFe] hydrogenases coupled to electron bifurcating subunits solved the enigma of how the otherwise highly endergonic reduction of the electron carrier ferredoxin can be carried out and how H2 production from NADH is possible. Complexes of [FeFe] hydrogenases with formate dehydrogenases revealed a novel enzymatic coupling of the two electron carriers H2 and formate. These novel hydrogenase enzyme complex could also contribute to biotechnological H2 production and H2 storage, both processes essential for an envisaged economy based on H2 as energy carrier.
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Affiliation(s)
- Kai Schuchmann
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Nilanjan Pal Chowdhury
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Volker Müller
- Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
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