1
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Li Y, Yang B, Kong Y, Tao Y, Zhao Z, Li Y, Zhang Y. Correlation between intracellular electron transfer and gene expression for electrically conductive pili in electroactive bacteria during anaerobic digestion with ethanol. WATER RESEARCH 2024; 265:122307. [PMID: 39180955 DOI: 10.1016/j.watres.2024.122307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/24/2024] [Accepted: 08/19/2024] [Indexed: 08/27/2024]
Abstract
Ethanol feeding has been widely documented as an economical and effective strategy for establishing direct interspecies electron transfer (DIET) during anaerobic digestion. However, the mechanisms involved are still unclear, especially on correlation between intracellular electron transfer in electroactive bacteria and their gene expression for electrically conductive pili (e-pili), the most essential electrical connection component for DIET. Upon cooling from room temperature, the conductivity of digester aggregates with ethanol exponentially increased by an order of magnitude (from 45.5 to 125.4 μS/cm), whereas which with its metabolites (acetaldehyde [from 40.5 to 54.4 μS/cm] or acetate [from 32.1 to 50.4 μS/cm]) did not increase significantly. In addition, the digester aggregates only with ethanol were observed with a strong dependence of conductivity on pH. Metagenomic and metatranscriptomic analysis showed that Desulfovibrio desulfuricans was the most dominant and metabolically active bacterium that contained and highly expressed the genes for e-pili. Abundance of genes encoding the total type IV pilus assembly proteins (6.72E-04 vs 1.24E-03, P < 0.05), PilA that determined the conductive properties (2.22E-04 vs 2.44E-04, P > 0.05), and PilB that proceeded the polymerization of pilin (1.56E-04 vs 3.52E-03, P < 0.05) with ethanol was lower than that with acetaldehyde. However, transcript abundance of these genes with ethanol was generally higher than that with acetaldehyde. In comparison to acetaldehyde, ethanol increased the transcript abundance of genes encoding the key enzymes involved in NADH/NAD+ transformation on complex I and ATP synthesis on complex V in intracellular electron transport chain. The improvement of intracellular electron transfer in D. desulfuricans suggested that electrons were intracellularly energized with high energy to activate e-pili during DIET.
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Affiliation(s)
- Yuan Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Bowen Yang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yaohui Kong
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yang Tao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Yang Li
- School of Chemical Engineering, Ocean and Life Sciences, Dalian University of Technology, Panjin 124221, China.
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China; School of Chemical Engineering, Ocean and Life Sciences, Dalian University of Technology, Panjin 124221, China
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2
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Wu Z, Ji Y, Liu G, Yu X, Shi K, Liang B, Freilich S, Jiang J. Electro-stimulation modulates syntrophic interactions in methanogenic toluene-degrading microbiota for enhanced functionality. WATER RESEARCH 2024; 260:121898. [PMID: 38865893 DOI: 10.1016/j.watres.2024.121898] [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: 03/06/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/14/2024]
Abstract
Syntrophy achieved via microbial cooperation is vital for anaerobic hydrocarbon degradation and methanogenesis. However, limited understanding of the metabolic division of labor and electronic interactions in electro-stimulated microbiota has impeded the development of enhanced biotechnologies for degrading hydrocarbons to methane. Here, compared to the non-electro-stimulated methanogenic toluene-degrading microbiota, electro-stimulation at 800 mV promoted toluene degradation and methane production efficiencies by 11.49 %-14.76 % and 75.58 %-290.11 %, respectively. Hydrocarbon-degrading gene bamA amplification and metagenomic sequencing analyses revealed that f_Syntrophobacteraceae MAG116 may act as a toluene degrader in the non-electro-stimulated microbiota, which was proposed to establish electron syntrophy with the acetoclastic methanogen Methanosarcina spp. (or Methanothrix sp.) through e-pili or shared acetate. In the electro-stimulated microbiota, 37.22 ± 4.33 % of Desulfoprunum sp. (affiliated f_Desulfurivibrionaceae MAG10) and 58.82 ± 3.74 % of the hydrogenotrophic methanogen Methanobacterium sp. MAG74 were specifically recruited to the anode and cathode, respectively. The potential electrogen f_Desulfurivibrionaceae MAG10 engaged in interspecies electron transfer with both syntroph f_Syntrophobacteraceae MAG116 and the anode, which might be facilitated by c-type cytochromes (e.g., ImcH, OmcT, and PilZ). Moreover, upon capturing electrons from the external circuit, the hydrogen-producing electrotroph Aminidesulfovibrio sp. MAG60 could share electrons and hydrogen with the methanogen Methanobacterium sp. MAG74, which uniquely harbored hydrogenase genes ehaA-R and ehbA-P. This study elucidates the microbial interaction mechanisms underlying the enhanced metabolic efficiency of the electro-stimulated methanogenic toluene-degrading microbiota, and emphasizes the significance of metabolic and electron syntrophic interactions in maintaining the stability of microbial community functionality.
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Affiliation(s)
- Zhiming Wu
- Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China; College of Life Sciences, Jiangxi Normal University, Nanchang 330022, China
| | - Yanhan Ji
- Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Guiping Liu
- Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Xin Yu
- Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Ke Shi
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Bin Liang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Shiri Freilich
- Newe-Ya'ar Research Center, Agricultural Research Organization, Ministry of Agriculture, Israel
| | - Jiandong Jiang
- Department of Microbiology, College of Life Sciences, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China.
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3
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Ma Y, Qu Y, Yao X, Xia C, Lv M, Lin X, Zhang L, Zhang M, Hu B. Unveiling the unique role of iron in the metabolism of methanogens: A review. ENVIRONMENTAL RESEARCH 2024; 250:118495. [PMID: 38367837 DOI: 10.1016/j.envres.2024.118495] [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: 12/26/2023] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/19/2024]
Abstract
Methanogens are the main participants in the carbon cycle, catalyzing five methanogenic pathways. Methanogens utilize different iron-containing functional enzymes in different methanogenic processes. Iron is a vital element in methanogens, which can serve as a carrier or reactant in electron transfer. Therefore, iron plays an important role in the growth and metabolism of methanogens. In this paper, we cast light on the types and functions of iron-containing functional enzymes involved in different methanogenic pathways, and the roles iron play in energy/substance metabolism of methanogenesis. Furthermore, this review provides certain guiding significance for lowering CH4 emissions, boosting the carbon sink capacity of ecosystems and promoting green and low-carbon development in the future.
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Affiliation(s)
- Yuxin Ma
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Qu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiangwu Yao
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chujun Xia
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Mengjie Lv
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiao Lin
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lili Zhang
- Beijing Enterprises Water Group Limited, Beijing, China
| | - Meng Zhang
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Baolan Hu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China.
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4
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Liang L, Zhao Z, Zhou H, Zhang Y. Insights into feasibility and microbial characterizations on simultaneous elimination of dissolved methane from anaerobic effluents and nitrate/nitrite reduction in a conventional anoxic reactor with magnetite. WATER RESEARCH 2024; 256:121567. [PMID: 38581983 DOI: 10.1016/j.watres.2024.121567] [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: 09/03/2023] [Revised: 03/25/2024] [Accepted: 04/02/2024] [Indexed: 04/08/2024]
Abstract
Discovery of nitrate/nitrite-dependent anaerobic methane oxidation (DAMO) challenges the conventional biological treatment processes, since it provides a possibility of simultaneously mitigating dissolved methane emissions from anaerobic effluents and reducing additional carbon sources for denitrification. Due to the slow growth of specialized DAMO microbes, this possibility has been just practiced with biofilms in membrane biofilm reactors or granular sludge in membrane bioreactors. In this study, simultaneous elimination of dissolved methane from anaerobic effluents and nitrate/nitrite reduction was achieved in a conventional anoxic reactor with magnetite. Calculations of electron flow balance showed that, with magnetite the eliminated dissolved methane was almost entirely used for nitrate/nitrite reduction, while without magnetite approximately 52 % of eliminated dissolved methane was converted to unknown organics. Metagenomic sequencing showed that, when dissolved methane served as an electron donor, the abundance of genes for reverse methanogenesis and denitrification dramatically increased, indicating that anaerobic oxidation of methane (AOM) coupled to nitrate/nitrite reduction occurred. Magnetite increased the abundance of genes encoding the key enzymes involved in whole reverse methanogenesis and Nir and Nor involved in denitrification, compared to that without magnetite. Analysis of microbial communities showed that, AOM coupled to nitrate/nitrite reduction was proceeded by syntrophic consortia comprised of methane oxidizers, Methanolinea and Methanobacterium, and nitrate/nitrite reducers, Armatimonadetes_gp5 and Thauera. With magnetite syntrophic consortia exchanged electrons more effectively than that without magnetite, further supporting the microbial growth.
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Affiliation(s)
- Lianfu Liang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Hao Zhou
- School of Chemical Engineering, Ocean and Life Sciences, Dalian University of Technology, Panjin 124221, China.
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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5
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Mei N, Tremblay PL, Wu Y, Zhang T. Proposed mechanisms of electron uptake in metal-corroding methanogens and their potential for CO 2 bioconversion applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171384. [PMID: 38432383 DOI: 10.1016/j.scitotenv.2024.171384] [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: 12/18/2023] [Revised: 02/28/2024] [Accepted: 02/28/2024] [Indexed: 03/05/2024]
Abstract
Some methanogens are electrotrophic bio-corroding microbes that can acquire electrons from solid surfaces including metals. In the laboratory, pure cultures of methanogenic cells oxidize iron-based materials including carbon steel, stainless steel, and Fe0. For buried or immersed pipelines or other metallic structures, methanogens are often major components of corroding biofilms with complex interspecies relationships. Models explaining how these microbes acquire electrons from solid donors are multifaceted and include electron transfer via redox mediators such as H2 or by direct contact through membrane proteins. Understanding the electron uptake (EU) routes employed by corroding methanogens is essential to develop efficient strategies for corrosion prevention. It is also beneficial for the development of bioenergy applications relying on methanogenic EU from solid donors such as bioelectromethanogenesis, hybrid photosynthesis, and the acceleration of anaerobic digestion with electroconductive particles. Many methanogenic species carrying out biocorrosion are the same ones forming the extensive abiotic-biological interfaces at the core of these bio-applications. This review will discuss the interactions between corrosive methanogens and metals and how the EU capability of these microbes can be harnessed for different sustainable biotechnologies.
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Affiliation(s)
- Nan Mei
- Institut WUT-AMU, Wuhan University of Technology, Wuhan 430070, PR China
| | - Pier-Luc Tremblay
- Institut WUT-AMU, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; Shaoxing Institute for Advanced Research, Wuhan University of Technology, Shaoxing 312300, PR China; Sanya Science and Education Innovation Park, Wuhan University of Technology, Sanya 572024, PR China
| | - Yuyang Wu
- Institut WUT-AMU, Wuhan University of Technology, Wuhan 430070, PR China
| | - Tian Zhang
- Institut WUT-AMU, Wuhan University of Technology, Wuhan 430070, PR China; School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; Shaoxing Institute for Advanced Research, Wuhan University of Technology, Shaoxing 312300, PR China; Sanya Science and Education Innovation Park, Wuhan University of Technology, Sanya 572024, PR China.
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6
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Dzofou Ngoumelah D, Heggeset TMB, Haugen T, Sulheim S, Wentzel A, Harnisch F, Kretzschmar J. Effect of model methanogens on the electrochemical activity, stability, and microbial community structure of Geobacter spp. dominated biofilm anodes. NPJ Biofilms Microbiomes 2024; 10:17. [PMID: 38443373 PMCID: PMC10915144 DOI: 10.1038/s41522-024-00490-z] [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: 03/09/2023] [Accepted: 02/20/2024] [Indexed: 03/07/2024] Open
Abstract
Combining anaerobic digestion (AD) and microbial electrochemical technologies (MET) in AD-MET holds great potential. Methanogens have been identified as one cause of decreased electrochemical activity and deterioration of Geobacter spp. biofilm anodes. A better understanding of the different interactions between methanogenic genera/species and Geobacter spp. biofilms is needed to shed light on the observed reduction in electrochemical activity and stability of Geobacter spp. dominated biofilms as well as observed changes in microbial communities of AD-MET. Here, we have analyzed electrochemical parameters and changes in the microbial community of Geobacter spp. biofilm anodes when exposed to three representative methanogens with different metabolic pathways, i.e., Methanosarcina barkeri, Methanobacterium formicicum, and Methanothrix soehngenii. M. barkeri negatively affected the performance and stability of Geobacter spp. biofilm anodes only in the initial batches. In contrast, M. formicicum did not affect the stability of Geobacter spp. biofilm anodes but caused a decrease in maximum current density of ~37%. M. soehngenii induced a coloration change of Geobacter spp. biofilm anodes and a decrease in the total transferred charge by ~40%. Characterization of biofilm samples after each experiment by 16S rRNA metabarcoding, whole metagenome nanopore sequencing, and shotgun sequencing showed a higher relative abundance of Geobacter spp. after exposure to M. barkeri as opposed to M. formicicum or M. soehngenii, despite the massive biofilm dispersal observed during initial exposure to M. barkeri.
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Affiliation(s)
- Daniel Dzofou Ngoumelah
- DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH (German Biomass Research Centre), Department of Biochemical Conversion, 04347, Leipzig, Germany
| | | | - Tone Haugen
- SINTEF Industry, Department of Biotechnology and Nanomedicine, 7034, Trondheim, Norway
| | - Snorre Sulheim
- SINTEF Industry, Department of Biotechnology and Nanomedicine, 7034, Trondheim, Norway
| | - Alexander Wentzel
- SINTEF Industry, Department of Biotechnology and Nanomedicine, 7034, Trondheim, Norway
| | - Falk Harnisch
- Helmholtz Centre for Environmental Research - UFZ, Department of Microbial Biotechnology, 04318, Leipzig, Germany
| | - Jörg Kretzschmar
- DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH (German Biomass Research Centre), Department of Biochemical Conversion, 04347, Leipzig, Germany.
- Zittau/Görlitz University of Applied Sciences, Faculty of Natural and Environmental Sciences, 02763, Zittau, Germany.
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7
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Yao S, Swanson CS, Cheng Z, He Q, Yuan H. Alternating polarity as a novel strategy for building synthetic microbial communities capable of robust Electro-Methanogenesis. BIORESOURCE TECHNOLOGY 2024; 395:130374. [PMID: 38280409 DOI: 10.1016/j.biortech.2024.130374] [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: 12/11/2023] [Revised: 01/08/2024] [Accepted: 01/22/2024] [Indexed: 01/29/2024]
Abstract
Electro-methanogenic microbial communities can produce biogas with high efficiency and have attracted extensive research interest. In this study an alternating polarity strategy was developed to build electro-methanogenic communities. In two-chamber bioelectrochemical systems amended with activated carbon, the electrode potential was alternated between +0.8 V and -0.4 V vs. standard hydrogen electrode every three days. Cumulative biogas production under alternating polarity increased from 45 L/L/kg-activated carbon after start-up to 125 L/L/kg after the 4th enrichment, significantly higher than that under intermittent cathode (-0.4 V/open circuit), continuous cathode (-0.4 V), and open circuit. The communities assembled under alternating polarity were electroactive and structurally different from those assembled under other conditions. One Methanobacterium population and two Geobacter populations were consistently abundant and active in the communities. Their 16S rRNA was up-regulated by electrode potentials. Bayesian networks inferred close associations between these populations. Overall, electro-methanogenic communities have been successfully assembled with alternating polarity.
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Affiliation(s)
- Shiyun Yao
- Department of Civil and Environmental Engineering, Temple University, Philadelphia, PA 19122, United States
| | - Clifford S Swanson
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Knoxville, TN 37996, United States
| | - Zhang Cheng
- Department of Civil and Environmental Engineering, Temple University, Philadelphia, PA 19122, United States
| | - Qiang He
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Knoxville, TN 37996, United States.
| | - Heyang Yuan
- Department of Civil and Environmental Engineering, Temple University, Philadelphia, PA 19122, United States.
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8
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Sobanaa M, Prathiviraj R, Selvin J, Prathaban M. A comprehensive review on methane's dual role: effects in climate change and potential as a carbon-neutral energy source. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:10379-10394. [PMID: 37884720 DOI: 10.1007/s11356-023-30601-w] [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: 08/03/2022] [Accepted: 10/18/2023] [Indexed: 10/28/2023]
Abstract
The unprecedented population and anthropogenic activity rise have challenged the future look up for shifts in global temperature and climate patterns. Anthropogenic activities such as land fillings, building dams, wetlands converting to lands, combustion of biomass, deforestation, mining, and the gas and coal industries have directly or indirectly increased catastrophic methane (CH4) emissions at an alarming rate. Methane is 25 times more potent trapping heat when compared to carbon dioxide (CO2) in the atmosphere. A rise in atmospheric methane, on a 20-year time scale, has an impact of 80 times greater than that of CO2. With increased population growth, waste generation is rising and is predicted to reach 6 Mt by 2025. CH4 emitted from landfills is a significant source that accounts for 40% of overall global methane emissions. Various mitigation and emissions reduction strategies could significantly reduce the global CH4 burden at a cost comparable to the parallel and necessary CO2 reduction measures, reversing the CH4 burden to pathways that achieve the goals of the Paris Agreement. CH4 mitigation directly benefits climate change, has collateral impacts on the economy, human health, and agriculture, and considerably supports CO2 mitigation. Utilizing the CO2 from the environment, methanogens produce methane and lower their carbon footprint. NGOs and the general public should act on time to overcome atmospheric methane emissions by utilizing the raw source for producing carbon-neutral fuel. However, more research potential is required for green energy production and to consider investigating the untapped potential of methanogens for dependable energy generation.
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Affiliation(s)
- Murugesan Sobanaa
- Department of Microbiology, Pondicherry University, Puducherry, 605014, India
| | | | - Joseph Selvin
- Department of Microbiology, Pondicherry University, Puducherry, 605014, India
| | - Munisamy Prathaban
- Department of Microbiology, Pondicherry University, Puducherry, 605014, India.
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9
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Meier D, van Grinsven S, Michel A, Eickenbusch P, Glombitza C, Han X, Fiskal A, Bernasconi S, Schubert CJ, Lever MA. Hydrogen-independent CO 2 reduction dominates methanogenesis in five temperate lakes that differ in trophic states. ISME COMMUNICATIONS 2024; 4:ycae089. [PMID: 38988698 PMCID: PMC11235125 DOI: 10.1093/ismeco/ycae089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 05/20/2024] [Accepted: 06/20/2024] [Indexed: 07/12/2024]
Abstract
Emissions of microbially produced methane (CH4) from lake sediments are a major source of this potent greenhouse gas to the atmosphere. The rates of CH4 production and emission are believed to be influenced by electron acceptor distributions and organic carbon contents, which in turn are affected by anthropogenic inputs of nutrients leading to eutrophication. Here, we investigate how eutrophication influences the abundance and community structure of CH4 producing Archaea and methanogenesis pathways across time-resolved sedimentary records of five Swiss lakes with well-characterized trophic histories. Despite higher CH4 concentrations which suggest higher methanogenic activity in sediments of eutrophic lakes, abundances of methanogens were highest in oligotrophic lake sediments. Moreover, while the methanogenic community composition differed significantly at the lowest taxonomic levels (OTU), depending on whether sediment layers had been deposited under oligotrophic or eutrophic conditions, it showed no clear trend in relation to in situ distributions of electron acceptors. Remarkably, even though methanogenesis from CO2-reduction was the dominant pathway in all sediments based on carbon isotope fractionation values, taxonomic identities, and genomes of resident methanogens, CO2-reduction with hydrogen (H2) was thermodynamically unfavorable based on measured reactant and product concentrations. Instead, strong correlations between genomic abundances of CO2-reducing methanogens and anaerobic bacteria with potential for extracellular electron transfer suggest that methanogenic CO2-reduction in lake sediments is largely powered by direct electron transfer from syntrophic bacteria without involvement of H2 as an electron shuttle.
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Affiliation(s)
- Dimitri Meier
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
- Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Dr. Hans-Frisch-Straße 1-3, 95448 Bayreuth, Germany
| | - Sigrid van Grinsven
- Department of Surface Waters-Research and Management, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Seestrasse 79, 6047 Kastanienbaum, Switzerland
- Geomicrobiology, Department of Geosciences, Eberhard Karls Universität Tübingen (Tübingen University), Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
| | - Anja Michel
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Philip Eickenbusch
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Clemens Glombitza
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Xingguo Han
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Annika Fiskal
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Stefano Bernasconi
- Department of Earth Sciences, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Geological Institute, Sonneggstrasse 5, 8092 Zurich, Switzerland
| | - Carsten J Schubert
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
- Department of Surface Waters-Research and Management, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Seestrasse 79, 6047 Kastanienbaum, Switzerland
| | - Mark A Lever
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
- Marine Science Institute, Department of Marine Sciences, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, United States
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10
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Song Y, Huang R, Li L, Du K, Zhu F, Song C, Yuan X, Wang M, Wang S, Ferry JG, Zhou S, Yan Z. Humic acid-dependent respiratory growth of Methanosarcina acetivorans involves pyrroloquinoline quinone. THE ISME JOURNAL 2023; 17:2103-2111. [PMID: 37737251 PMCID: PMC10579383 DOI: 10.1038/s41396-023-01520-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023]
Abstract
Although microbial humus respiration plays a critical role in organic matter decomposition and biogeochemical cycling of elements in diverse anoxic environments, the role of methane-producing species (methanogens) is not well defined. Here we report that a major fraction of humus, humic acid reduction enhanced the growth of Methanosarcina acetivorans above that attributed to methanogenesis when utilizing the energy sources methanol or acetate, results which showed both respiratory and fermentative modes of energy conservation. Growth characteristics with methanol were the same for an identically cultured mutant deleted for the gene encoding a multi-heme cytochrome c (MmcA), results indicating MmcA is not essential for respiratory electron transport to humic acid. Transcriptomic analyses revealed that growth with humic acid promoted the upregulation of genes annotated as cell surface pyrroloquinoline quinone (PQQ)-binding proteins. Furthermore, PQQ isolated from the membrane fraction was more abundant in humic acid-respiring cells, and the addition of PQQ improved efficiency of the extracellular electron transport. Given that the PQQ-binding proteins are widely distributed in methanogens, the findings extend current understanding of microbial humus respiration in the context of global methane dynamics.
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Affiliation(s)
- Yuanxu Song
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Rui Huang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Ling Li
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, 266237, Shandong, China
| | - Kaifeng Du
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Fanping Zhu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Chao Song
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Xianzheng Yuan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Mingyu Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, 266237, Shandong, China.
| | - Shuguang Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
| | - James G Ferry
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zhen Yan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
- Suzhou Research Institute, Shandong University, Suzhou, 215123, Jiangsu, China.
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11
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Ao Z, Li Y, Li Y, Zhao Z, Zhang Y. Facilitating direct interspecies electron transfer in anaerobic digestion via speeding up transmembrane transport of electrons and CO 2 reduction in methanogens by Na + adjustment. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 170:252-260. [PMID: 37729842 DOI: 10.1016/j.wasman.2023.09.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/08/2023] [Accepted: 09/15/2023] [Indexed: 09/22/2023]
Abstract
The possibility of facilitating direct interspecies electron transfer (DIET) in anaerobic digestion with different concentrations of NaCl was explored. Additional NaCl at 2 or 4 g/L strengthened anaerobic digestion to resist the high-organic loading rate impacts, whereas the higher concentrations of NaCl (6 or 8 g/L) suppressed methanogenesis. Additional MgCl2 with the same ion strength as NaCl at 2 g/L had no effect on performances. Additional NaCl at 2 or 4 g/L dramatically increased the abundance of Methanosarcina species (20.7%/23.4% vs 8.6%) and stimulated the growth of Sphaerochaeta and Petrimonas species that could transfer electrons to the soluble Fe(III) or elemental sulfur. Electrochemical evidences showed that, additional NaCl at 2 or 4 g/L increased capacitances and decreased charge transfer resistances of Methanosarcina-dominant communities. Metagenomic evidences showed that, additional NaCl at 2 or 4 g/L increased the abundance of genes that encoded the type IV pilus assembly proteins (1.98E-04/1.87E-04 vs 1.85E-04) and cytochrome c-like proteins (5.51E-04/5.60E-04 vs 5.31E-04). In addition, additional NaCl at 2 or 4 g/L increased the abundance of genes for methanophenazine (MP)/MPH2 transformation (1.04E-05/1.24E-05 vs 8.06E-06) and CO2 reduction (1.64E-03/1.86E-03 vs 1.06E-03), suggesting a rapid transmembrane transport of electrons and CO2 reduction in methanogens. Both processes were closely associated with F420/F420H2 transformation that required ATP. Additional NaCl at 2 or 4 g/L increased the yield of ATP (256.0/249.3 vs 231.8 nmol/L) that might promote F420/F420H2 transformation in methanogens, which overcame the thermodynamic limitations of combining electrons with protons for the reduction of CO2 to methane and facilitated DIET.
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Affiliation(s)
- Zhipeng Ao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yuan Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yang Li
- School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Dalian University of Technology), Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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12
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Chai F, Li L, Wang W, Xue S, Liu J. Electro-stimulated anaerobic oxidation of methane with synergistic denitrification by adding AQS: Electron transfer mode and mechanism. ENVIRONMENTAL RESEARCH 2023; 229:115997. [PMID: 37105293 DOI: 10.1016/j.envres.2023.115997] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/10/2023] [Accepted: 04/24/2023] [Indexed: 05/21/2023]
Abstract
Denitrifying anaerobic methane-oxidizing (DAMO) processes, which link anaerobic methane oxidation (AMO) and denitrification, have a promising prospect in anaerobic wastewater treatment. In bioelectrochemical systems (BES), DAMO consortium presented potent metabolic activity. However, the extracellular electron transfer (EET) in BES was poorly understood. This study investigated the EET mechanisms and modes of electron transport in BES dominated by anaerobic methanotrophic bacteria. In the bioreactors with the auxiliary voltage of 0.5 and 1.1 V, named EMN-0.5 and EMN-1.1, respectively, biological voltages of 0.198 and 0.329 V were generated with power densities of 0.6 and 1.20 mW/m2, after removing the voltage. High throughput and metagenome analyses demonstrated that main methanotrophs were DAMO bacteria and Methylocystis sp. The electroactive bacteria detected were Pseudomonas sp., Hypomicrobium sp., Thiobacillus sp, and Rhodococcus sp. The pil, cytochrome c, hdr, and he/fp genes related to EET were present on the electrode surfaces. Carbon 13 isotope tracing and chemicals analysis by GC-MS exhibited that methanol was an intermediate product released to extracellular environment and acted as the electronic carrier to drive the EET in methane oxidation. Extracellular electron transfer was achieved through the collaboration of DAMO bacteria, Methylocystis sp., and Pseudomonas sp. Anthraquinone 2-sulfonic acid ester (AQS) could improve the rate of electron transfer to the extracellular space, especially in the EMN-0.5 reaction system. This study provides a new understanding of AMO consortium metabolism in BES and may provide a scientific basis for developing methane control technology.
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Affiliation(s)
- Fengguang Chai
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China; School of Ecology and Environment, Zhengzhou University, Zhengzhou, 450001, China
| | - Lin Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing, 101408, China.
| | - Wenwen Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing, 100085, China; University of Chinese Academy of Sciences, 19(A) Yuquan Road, Shijingshan District, Beijing, 100049, China
| | - Song Xue
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Junxin Liu
- University of Chinese Academy of Sciences, 19(A) Yuquan Road, Shijingshan District, Beijing, 100049, China
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13
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Barrera-Rojas J, Gurubel-Tun KJ, Ríos-Castro E, López-Méndez MC, Sulbarán-Rangel B. An Initial Proteomic Analysis of Biogas-Related Metabolism of Euryarchaeota Consortia in Sediments from the Santiago River, México. Microorganisms 2023; 11:1640. [PMID: 37512813 PMCID: PMC10384328 DOI: 10.3390/microorganisms11071640] [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: 04/30/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
In this paper, sediments from the Santiago River were characterized to look for an alternative source of inoculum for biogas production. A proteomic analysis of methane-processing archaea present in these sediments was carried out. The Euryarchaeota superkingdom of archaea is responsible for methane production and methane assimilation in the environment. The Santiago River is a major river in México with great pollution and exceeded recovery capacity. Its sediments could contain nutrients and the anaerobic conditions for optimal growth of Euryarchaeota consortia. Batch bioreactor experiments were performed, and a proteomic analysis was conducted with current database information. The maximum biogas production was 266 NmL·L-1·g VS-1, with 33.34% of methane, and for proteomics, 3206 proteins were detected from 303 species of 69 genera. Most of them are metabolically versatile members of the genera Methanosarcina and Methanosarcinales, both with 934 and 260 proteins, respectively. These results showed a diverse euryarcheotic species with high potential to methane production. Although related proteins were found and could be feeding this metabolism through the methanol and acetyl-CoA pathways, the quality obtained from the biogas suggests that this metabolism is not the main one in carbon use, possibly the sum of several conditions including growth conditions and the pollution present in these sediments.
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Affiliation(s)
- Jesús Barrera-Rojas
- Department of Water and Energy, Campus Tonalá, University of Guadalajara, Tonalá 45425, Mexico
| | - Kelly Joel Gurubel-Tun
- Department of Water and Energy, Campus Tonalá, University of Guadalajara, Tonalá 45425, Mexico
| | - Emmanuel Ríos-Castro
- Laboratorios Nacionales de Servicios Experimentales, Centro de Investigación y Estudios Avanzados del IPN, Ciudad de México 07000, Mexico
| | - María Cristina López-Méndez
- Wetlands and Environmental Sustainability Laboratory, Division of Graduate Studies and Research, Tecnológico Nacional de México/ITS de Misantla, Veracruz 93850, Mexico
| | - Belkis Sulbarán-Rangel
- Department of Water and Energy, Campus Tonalá, University of Guadalajara, Tonalá 45425, Mexico
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14
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Lever MA, Alperin MJ, Hinrichs KU, Teske A. Zonation of the active methane-cycling community in deep subsurface sediments of the Peru trench. Front Microbiol 2023; 14:1192029. [PMID: 37250063 PMCID: PMC10213550 DOI: 10.3389/fmicb.2023.1192029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 04/24/2023] [Indexed: 05/31/2023] Open
Abstract
The production and anaerobic oxidation of methane (AOM) by microorganisms is widespread in organic-rich deep subseafloor sediments. Yet, the organisms that carry out these processes remain largely unknown. Here we identify members of the methane-cycling microbial community in deep subsurface, hydrate-containing sediments of the Peru Trench by targeting functional genes of the alpha subunit of methyl coenzyme M reductase (mcrA). The mcrA profile reveals a distinct community zonation that partially matches the zonation of methane oxidizing and -producing activity inferred from sulfate and methane concentrations and carbon-isotopic compositions of methane and dissolved inorganic carbon (DIC). McrA appears absent from sulfate-rich sediments that are devoid of methane, but mcrA sequences belonging to putatively methane-oxidizing ANME-1a-b occur from the zone of methane oxidation to several meters into the methanogenesis zone. A sister group of ANME-1a-b, referred to as ANME-1d, and members of putatively aceticlastic Methanothrix (formerly Methanosaeta) occur throughout the remaining methanogenesis zone. Analyses of 16S rRNA and mcrA-mRNA indicate that the methane-cycling community is alive throughout (rRNA to 230 mbsf) and active in at least parts of the sediment column (mRNA at 44 mbsf). Carbon-isotopic depletions of methane relative to DIC (-80 to -86‰) suggest mostly methane production by CO2 reduction and thus seem at odds with the widespread detection of ANME-1 and Methanothrix. We explain this apparent contradiction based on recent insights into the metabolisms of both ANME-1 and Methanothricaceae, which indicate the potential for methanogenetic growth by CO2 reduction in both groups.
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Affiliation(s)
- Mark A. Lever
- Department of Marine Science, Marine Science Institute, University of Texas at Austin, Port Aransas, TX, United States
- Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Marc J. Alperin
- Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kai-Uwe Hinrichs
- Organic Geochemistry Group, MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Andreas Teske
- Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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15
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Verma M, Singh V, Mishra V. Moving towards the enhancement of extracellular electron transfer in electrogens. World J Microbiol Biotechnol 2023; 39:130. [PMID: 36959310 DOI: 10.1007/s11274-023-03582-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/15/2023] [Indexed: 03/25/2023]
Abstract
Electrogens are very common in nature and becoming a contemporary theme for research as they can be exploited for extracellular electron transfer. Extracellular electron transfer is the key mechanism behind bioelectricity generation and bioremediation of pollutants via microbes. Extracellular electron transfer mechanisms for electrogens other than Shewanella and Geobacter are less explored. An efficient extracellular electron transfer system is crucial for the sustainable future of bioelectrochemical systems. At present, the poor extracellular electron transfer efficiency remains a decisive factor in limiting the development of efficient bioelectrochemical systems. In this review article, the EET mechanisms in different electrogens (bacteria and yeast) have been focused. Apart from the well-known electron transfer mechanisms of Shewanella oneidensis and Geobacter metallireducens, a brief introduction of the EET pathway in Rhodopseudomonas palustris TIE-1, Sideroxydans lithotrophicus ES-1, Thermincola potens JR, Lysinibacillus varians GY32, Carboxydothermus ferrireducens, Enterococcus faecalis and Saccharomyces cerevisiae have been included. In addition to this, the article discusses the several approaches to anode modification and genetic engineering that may be used in order to increase the rate of extracellular electron transfer. In the side lines, this review includes the engagement of the electrogens for different applications followed by the future perspective of efficient extracellular electron transfer.
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Affiliation(s)
- Manisha Verma
- School of Biochemical Engineering, IIT (BHU), 221005, Varanasi, India
| | - Vishal Singh
- School of Biochemical Engineering, IIT (BHU), 221005, Varanasi, India
| | - Vishal Mishra
- School of Biochemical Engineering, IIT (BHU), 221005, Varanasi, India.
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16
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Thomsen J, Schmitz RA. Generating a Small Shuttle Vector for Effective Genetic Engineering of Methanosarcina mazei Allowed First Insights in Plasmid Replication Mechanism in the Methanoarchaeon. Int J Mol Sci 2022; 23:ijms231911910. [PMID: 36233214 PMCID: PMC9569500 DOI: 10.3390/ijms231911910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/04/2022] [Accepted: 10/05/2022] [Indexed: 11/16/2022] Open
Abstract
Due to their role in methane production, methanoarchaea are of high ecological relevance and genetic systems have been ever more established in the last two decades. The system for protein expression in Methanosarcina using a comprehensive shuttle vector is established; however, details about its replication mechanism in methanoarchaea remain unknown. Here, we report on a significant optimisation of the rather large shuttle vector pWM321 (8.9 kbp) generated by Metcalf through a decrease in its size by about 35% by means of the deletion of several non-coding regions and the ssrA gene. The resulting plasmid (pRS1595) still stably replicates in M. mazei and—most likely due to its reduced size—shows a significantly higher transformation efficiency compared to pWM321. In addition, we investigate the essential gene repA, coding for a rep type protein. RepA was heterologously expressed in Escherichia coli, purified and characterised, demonstrating the significant binding and nicking activity of supercoiled plasmid DNA. Based on our findings we propose that the optimised shuttle vector replicates via a rolling circle mechanism with RepA as the initial replication protein in Methanosarcina. On the basis of bioinformatic comparisons, we propose the presence and location of a double-strand and a single-strand origin, which need to be further verified.
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17
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Community Structure and Microbial Associations in Sediment-Free Methanotrophic Enrichment Cultures from a Marine Methane Seep. Appl Environ Microbiol 2022; 88:e0210921. [PMID: 35604226 DOI: 10.1128/aem.02109-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Syntrophic consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB) consume large amounts of methane and serve as the foundational microorganisms in marine methane seeps. Despite their importance in the carbon cycle, research on the physiology of ANME-SRB consortia has been hampered by the slow growth and complex physicochemical environment the consortia inhabit. Here, we report successful sediment-free enrichment of ANME-SRB consortia from deep-sea methane seep sediments in the Santa Monica Basin, California. Anoxic Percoll density gradients and size-selective filtration were used to separate ANME-SRB consortia from sediment particles and single cells to accelerate the cultivation process. Over a 3-year period, a subset of the sediment-associated ANME and SRB lineages, predominantly comprised of ANME-2a/2b ("Candidatus Methanocomedenaceae") and their syntrophic bacterial partners, SEEP-SRB1/2, adapted and grew under defined laboratory conditions. Metagenome-assembled genomes from several enrichments revealed that ANME-2a, SEEP-SRB1, and Methanococcoides in different enrichments from the same inoculum represented distinct species, whereas other coenriched microorganisms were closely related at the species level. This suggests that ANME, SRB, and Methanococcoides are more genetically diverse than other members in methane seeps. Flow cytometry sorting and sequencing of cell aggregates revealed that Methanococcoides, Anaerolineales, and SEEP-SRB1 were overrepresented in multiple ANME-2a cell aggregates relative to the bulk metagenomes, suggesting they were physically associated and possibly interacting. Overall, this study represents a successful case of selective cultivation of anaerobic slow-growing microorganisms from sediments based on their physical characteristics, introducing new opportunities for detailed genomic, physiological, biochemical, and ecological analyses. IMPORTANCE Biological anaerobic oxidation of methane (AOM) coupled with sulfate reduction represents a large methane sink in global ocean sediments. Methane consumption is carried out by syntrophic archaeal-bacterial consortia and fuels a unique ecosystem, yet the interactions in these slow-growing syntrophic consortia and with other associated community members remain poorly understood. The significance of this study is the establishment of sediment-free enrichment cultures of anaerobic methanotrophic archaea and sulfate-reducing bacteria performing AOM with sulfate using selective cultivation approaches based on size, density, and metabolism. By reconstructing microbial genomes and analyzing community composition of the enrichment cultures and cell aggregates, we shed light on the diversity of microorganisms physically associated with AOM consortia beyond the core syntrophic partners. These enrichment cultures offer simplified model systems to extend our understanding of the diversity of microbial interactions within marine methane seeps.
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18
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Jiang Z, Yu Q, Sun C, Wang Z, Jin Z, Zhu Y, Zhao Z, Zhang Y. Additional electric field alleviates acidity suppression in anaerobic digestion of kitchen wastes via enriching electro-active methanogens in cathodic biofilms. WATER RESEARCH 2022; 212:118118. [PMID: 35091224 DOI: 10.1016/j.watres.2022.118118] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/15/2022] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
The aim of this study was to investigate the feasibility that the suppression of acidity in anaerobic digestion of kitchen wastes could be alleviated with additional electric field. The results showed that, the accumulation of acidity seriously suppressed methanogenesis, and no methane was detected in the electrode-supplemented digester without applied voltage. In contrast, with applied voltages of 0.6-1.2 V, the suppression of acidity was alleviated, and methane production rates reached 558-669 L/kg-volatile suspended solid that were higher than that previously reported with carbon-based conductive materials, such as granular active carbon and biochar. Although the reduced peak with a potential ranging from -0.3 V to -0.2 V close to the reduced potential of CO2/CH4 detected via cyclic voltammetry, the maximum methane yield derived from cathodic reduction of CO2 only accounted for 0.13-0.33% of total methane yield with applied voltages. Microbial community analysis showed that, Methanosarcina species were specially enriched with applied voltages, accounting for ca. 40-70% of the communities. Together with the increase in the relative abundance of Syntrophomonas species, Methanosarcina species directly accepting electrons from Syntrophomonas species via DIET might be the primary reason for alleviating the suppression of acidity. Further investigations via three-dimensional excitation emission matrix and in-situ electrochemical Fourier transform infrared spectroscopy found that additional electric field stimulated the secretion of EPS primarily comprised of protein-like substance, which might mediate the EET between Syntrophomonas and Methanosarcina species.
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Affiliation(s)
- Zhihao Jiang
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Qilin Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Cheng Sun
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhenxin Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhen Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yahui Zhu
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
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19
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Lovley DR. Electrotrophy: Other microbial species, iron, and electrodes as electron donors for microbial respirations. BIORESOURCE TECHNOLOGY 2022; 345:126553. [PMID: 34906705 DOI: 10.1016/j.biortech.2021.126553] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Electrotrophy, the growth of microbes on extracellular electron donors, drives important biogeochemical cycles and has practical applications. Studies of Fe(II)-based electrotrophy have provided foundational cytochrome-based mechanistic models for electron transport into cells. Direct electron uptake from other microbial species, Fe(0), or cathodes is of intense interest due to its potential roles in the production and anaerobic oxidation of methane, corrosion, and bioelectrochemical technologies. Other cells or Fe(0) can serve as the sole electron donor supporting the growth of several Geobacter and methanogen strains that are unable to use H2 as an electron donor, providing strong evidence for electrotrophy. Additional evidence for electrotrophy in Geobacter strains and Methanosarcina acetivorans is a requirement for outer-surface c-type cytochromes. However, in most instances claims for electrotrophy in anaerobes are based on indirect inference and the possibility that H2 is actually the electron donor supporting growth has not been rigorously excluded.
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Affiliation(s)
- Derek R Lovley
- Electrobiomaterials Institute, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819, China; Department of Microbiology and Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, MA, USA.
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20
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Zhang X, Yuan Z, Hu S. Anaerobic oxidation of methane mediated by microbial extracellular respiration. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:790-804. [PMID: 34523810 DOI: 10.1111/1758-2229.13008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/25/2021] [Accepted: 08/28/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic oxidation of methane (AOM) can be microbially mediated by the reduction of different terminal electron acceptors. AOM coupled to reduction of sulfate, manganese/iron oxides, humic substances, selenate, arsenic and other artificial extracellular electron acceptors are recognized as processes associated with microbial extracellular respiration. In these processes, methane-oxidizing archaea transfer electrons to external electron acceptors or to interdependent microbial species, which are mechanistically dependent on versatile extracellular electron transfer (EET) pathways. This review compiles recent progress in the research of electromicrobiology of AOM based on the catalogue of different electron acceptors. Naturally distributed and artificially constructed EET-mediated AOM is summarized, with the discussion of their environmental importance and application potentials. The diversity of responsible microorganisms involved in EET-mediated AOM is discussed with both methane-oxidizing archaea and their putative bacterial partners. More importantly, the review highlights progress and deficiencies in our understanding of EET pathways in EET-mediated AOM, raising open research questions for future research.
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Affiliation(s)
- Xueqin Zhang
- Advanced Water Management Centre, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Shihu Hu
- Advanced Water Management Centre, The University of Queensland, Brisbane, Qld, 4072, Australia
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