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Portela PC, Shipps CC, Shen C, Srikanth V, Salgueiro CA, Malvankar NS. Widespread extracellular electron transfer pathways for charging microbial cytochrome OmcS nanowires via periplasmic cytochromes PpcABCDE. Nat Commun 2024; 15:2434. [PMID: 38509081 PMCID: PMC10954620 DOI: 10.1038/s41467-024-46192-0] [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: 08/04/2023] [Accepted: 02/19/2024] [Indexed: 03/22/2024] Open
Abstract
Extracellular electron transfer (EET) via microbial nanowires drives globally-important environmental processes and biotechnological applications for bioenergy, bioremediation, and bioelectronics. Due to highly-redundant and complex EET pathways, it is unclear how microbes wire electrons rapidly (>106 s-1) from the inner-membrane through outer-surface nanowires directly to an external environment despite a crowded periplasm and slow (<105 s-1) electron diffusion among periplasmic cytochromes. Here, we show that Geobacter sulfurreducens periplasmic cytochromes PpcABCDE inject electrons directly into OmcS nanowires by binding transiently with differing efficiencies, with the least-abundant cytochrome (PpcC) showing the highest efficiency. Remarkably, this defined nanowire-charging pathway is evolutionarily conserved in phylogenetically-diverse bacteria capable of EET. OmcS heme reduction potentials are within 200 mV of each other, with a midpoint 82 mV-higher than reported previously. This could explain efficient EET over micrometres at ultrafast (<200 fs) rates with negligible energy loss. Engineering this minimal nanowire-charging pathway may yield microbial chassis with improved performance.
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Affiliation(s)
- Pilar C Portela
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Catharine C Shipps
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Cong Shen
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Vishok Srikanth
- Microbial Sciences Institute, Yale University, West Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Carlos A Salgueiro
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
| | - Nikhil S Malvankar
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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2
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Neu J, Shipps CC, Guberman-Pfeffer MJ, Shen C, Srikanth V, Spies JA, Kirchhofer ND, Yalcin SE, Brudvig GW, Batista VS, Malvankar NS. Microbial biofilms as living photoconductors due to ultrafast electron transfer in cytochrome OmcS nanowires. Nat Commun 2022; 13:5150. [PMID: 36071037 PMCID: PMC9452534 DOI: 10.1038/s41467-022-32659-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 08/09/2022] [Indexed: 11/09/2022] Open
Abstract
Light-induced microbial electron transfer has potential for efficient production of value-added chemicals, biofuels and biodegradable materials owing to diversified metabolic pathways. However, most microbes lack photoactive proteins and require synthetic photosensitizers that suffer from photocorrosion, photodegradation, cytotoxicity, and generation of photoexcited radicals that are harmful to cells, thus severely limiting the catalytic performance. Therefore, there is a pressing need for biocompatible photoconductive materials for efficient electronic interface between microbes and electrodes. Here we show that living biofilms of Geobacter sulfurreducens use nanowires of cytochrome OmcS as intrinsic photoconductors. Photoconductive atomic force microscopy shows up to 100-fold increase in photocurrent in purified individual nanowires. Photocurrents respond rapidly (<100 ms) to the excitation and persist reversibly for hours. Femtosecond transient absorption spectroscopy and quantum dynamics simulations reveal ultrafast (~200 fs) electron transfer between nanowire hemes upon photoexcitation, enhancing carrier density and mobility. Our work reveals a new class of natural photoconductors for whole-cell catalysis. Despite enormous potential of solar-driven biocatalysis, most living systems lack photoactive proteins and require toxic and expensive synthetic materials limiting the performance. Here, a class of natural photoconductors is demonstrated through sub-picosecond heme-to-heme electron transfer in bacteria-produced protein nanowires.
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Affiliation(s)
- Jens Neu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. .,Microbial Sciences Institute, Yale University, West Haven, CT, USA.
| | - Catharine C Shipps
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Matthew J Guberman-Pfeffer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Cong Shen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Vishok Srikanth
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Jacob A Spies
- Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - Sibel Ebru Yalcin
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, West Haven, CT, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, CT, USA
| | | | - Nikhil S Malvankar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. .,Microbial Sciences Institute, Yale University, West Haven, CT, USA.
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3
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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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4
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Using Oxidative Electrodes to Enrich Novel Members in the Desulfobulbaceae Family from Intertidal Sediments. Microorganisms 2021; 9:microorganisms9112329. [PMID: 34835454 PMCID: PMC8618199 DOI: 10.3390/microorganisms9112329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/21/2021] [Accepted: 11/08/2021] [Indexed: 01/04/2023] Open
Abstract
Members in the family of Desulfobulbaceae may be influential in various anaerobic microbial communities, including those in anoxic aquatic sediments and water columns, and within wastewater treatment facilities and bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs). However, the diversity and roles of the Desulfobulbaceae in these communities have received little attention, and large portions of this family remain uncultured. Here we expand on findings from an earlier study (Li, Reimers, and Alleau, 2020) to more fully characterize Desulfobulbaceae that became prevalent in biofilms on oxidative electrodes of bioelectrochemical reactors. After incubations, DNA extraction, microbial community analyses, and microscopic examination, we found that a group of uncultured Desulfobulbaceae were greatly enriched on electrode surfaces. These Desulfobulbaceae appeared to form filaments with morphological features ascribed to cable bacteria, but the majority were taxonomically distinct from recognized cable bacteria genera. Thus, the present study provides new information about a group of Desulfobulbaceae that can exhibit filamentous morphologies and respire on the oxidative electrodes. While the phylogeny of cable bacteria is still being defined and updated, further enriching these members can contribute to the overall understanding of cable bacteria and may also lead to identification of successful isolation strategies.
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5
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Lui LM, Majumder ELW, Smith HJ, Carlson HK, von Netzer F, Fields MW, Stahl DA, Zhou J, Hazen TC, Baliga NS, Adams PD, Arkin AP. Mechanism Across Scales: A Holistic Modeling Framework Integrating Laboratory and Field Studies for Microbial Ecology. Front Microbiol 2021; 12:642422. [PMID: 33841364 PMCID: PMC8024649 DOI: 10.3389/fmicb.2021.642422] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Over the last century, leaps in technology for imaging, sampling, detection, high-throughput sequencing, and -omics analyses have revolutionized microbial ecology to enable rapid acquisition of extensive datasets for microbial communities across the ever-increasing temporal and spatial scales. The present challenge is capitalizing on our enhanced abilities of observation and integrating diverse data types from different scales, resolutions, and disciplines to reach a causal and mechanistic understanding of how microbial communities transform and respond to perturbations in the environment. This type of causal and mechanistic understanding will make predictions of microbial community behavior more robust and actionable in addressing microbially mediated global problems. To discern drivers of microbial community assembly and function, we recognize the need for a conceptual, quantitative framework that connects measurements of genomic potential, the environment, and ecological and physical forces to rates of microbial growth at specific locations. We describe the Framework for Integrated, Conceptual, and Systematic Microbial Ecology (FICSME), an experimental design framework for conducting process-focused microbial ecology studies that incorporates biological, chemical, and physical drivers of a microbial system into a conceptual model. Through iterative cycles that advance our understanding of the coupling across scales and processes, we can reliably predict how perturbations to microbial systems impact ecosystem-scale processes or vice versa. We describe an approach and potential applications for using the FICSME to elucidate the mechanisms of globally important ecological and physical processes, toward attaining the goal of predicting the structure and function of microbial communities in chemically complex natural environments.
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Affiliation(s)
- Lauren M. Lui
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Erica L.-W. Majumder
- Department of Bacteriology, University of Wisconsin–Madison, Madison, WI, United States
| | - Heidi J. Smith
- Center for Biofilm Engineering, Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Hans K. Carlson
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Frederick von Netzer
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, United States
| | - Matthew W. Fields
- Center for Biofilm Engineering, Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - David A. Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, United States
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology & Plant Biology, School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, United States
| | - Terry C. Hazen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Knoxville, TN, United States
| | | | - Paul D. Adams
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Adam P. Arkin
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
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6
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Zhang X, Rabiee H, Frank J, Cai C, Stark T, Virdis B, Yuan Z, Hu S. Enhancing methane oxidation in a bioelectrochemical membrane reactor using a soluble electron mediator. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:173. [PMID: 33088343 PMCID: PMC7568384 DOI: 10.1186/s13068-020-01808-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/30/2020] [Indexed: 06/02/2023]
Abstract
BACKGROUND Bioelectrochemical methane oxidation catalysed by anaerobic methanotrophic archaea (ANME) is constrained by limited methane bioavailability as well as by slow kinetics of extracellular electron transfer (EET) of ANME. In this study, we tested a combination of two strategies to improve the performance of methane-driven bioelectrochemical systems that includes (1) the use of hollow fibre membranes (HFMs) for efficient methane delivery to the ANME organisms and (2) the amendment of ferricyanide, an effective soluble redox mediator, to the liquid medium to enable electrochemical bridging between the ANME organisms and the anode, as well as to promote EET kinetics of ANME. RESULTS The combined use of HFMs and the soluble mediator increased the performance of ANME-based bioelectrochemical methane oxidation, enabling the delivery of up to 196 mA m-2, thereby outperforming the control system by 244 times when HFMs were pressurized at 1.6 bar. CONCLUSIONS Improving methane delivery and EET are critical to enhance the performance of bioelectrochemical methane oxidation. This work demonstrates that by process engineering optimization, energy recovery from methane through its direct oxidation at relevant rates is feasible.
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Affiliation(s)
- Xueqin Zhang
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
| | - Hesamoddin Rabiee
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
| | - Joshua Frank
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
| | - Chen Cai
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
| | - Terra Stark
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, 4072 Australia
- Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, 4072 Australia
| | - Bernardino Virdis
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
| | - Shihu Hu
- Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia
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7
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Zhang S, Merino N, Okamoto A, Gedalanga P. Interkingdom microbial consortia mechanisms to guide biotechnological applications. Microb Biotechnol 2018; 11:833-847. [PMID: 30014573 PMCID: PMC6116752 DOI: 10.1111/1751-7915.13300] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 01/01/2023] Open
Abstract
Microbial consortia are capable of surviving diverse conditions through the formation of synergistic population-level structures, such as stromatolites, microbial mats and biofilms. Biotechnological applications are poised to capitalize on these unique interactions. However, current artificial co-cultures constructed for societal benefits, including biosynthesis, agriculture and bioremediation, face many challenges to perform as well as natural consortia. Interkingdom microbial consortia tend to be more robust and have higher productivity compared with monocultures and intrakingdom consortia, but the control and design of these diverse artificial consortia have received limited attention. Further, feasible research techniques and instrumentation for comprehensive mechanistic insights have only recently been established for interkingdom microbial communities. Here, we review these recent advances in technology and our current understanding of microbial interaction mechanisms involved in sustaining or developing interkingdom consortia for biotechnological applications. Some of the interactions among members from different kingdoms follow similar mechanisms observed for intrakingdom microbial consortia. However, unique interactions in interkingdom consortia, including endosymbiosis or interkingdom-specific cell-cell interactions, provide improved mitigation to external stresses and inhibitory compounds. Furthermore, antagonistic interactions among interkingdom species can promote fitness, diversification and adaptation, along with the production of beneficial metabolites and enzymes for society. Lastly, we shed light on future research directions to develop study methods at the level of metabolites, genes and meta-omics. These potential research methods could lead to the control and utilization of highly diverse microbial communities.
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Affiliation(s)
- Shu Zhang
- Global Research Center for Environment and Energy based on Nanomaterials ScienceNational Institute for Material Science1‐1 NamikiTsukubaIbarakiJapan
- Department of Molecular Microbiology and ImmunologyNorris Comprehensive Cancer CenterUniversity of Southern California1441 Eastlake StreetLos AngelesCA90033USA
- Present address:
Section of Infection and ImmunityHerman Ostrow School of DentistryUniversity of Southern CaliforniaCA90089‐0641USA
| | - Nancy Merino
- Earth‐Life Science InstituteTokyo Institute of Technology, 2‐12‐1‐I7E‐323Ookayama, Meguro‐kuTokyo 152‐8550Japan
- Department of Earth SciencesUniversity of Southern California, 835 Bloom Walk, SHS 562Los AngelesCA 90089‐0740USA
| | - Akihiro Okamoto
- Global Research Center for Environment and Energy based on Nanomaterials ScienceNational Institute for Material Science1‐1 NamikiTsukubaIbarakiJapan
| | - Phillip Gedalanga
- Department of Health ScienceCalifornia State University Fullerton, 800 North State College BoulevardFullertonCA 92831‐3599USA
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8
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Li C, Lesnik KL, Liu H. Stay connected: Electrical conductivity of microbial aggregates. Biotechnol Adv 2017; 35:669-680. [PMID: 28768145 DOI: 10.1016/j.biotechadv.2017.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 01/01/2023]
Abstract
The discovery of direct extracellular electron transfer offers an alternative to the traditional understanding of diffusional electron exchange via small molecules. The establishment of electronic connections between electron donors and acceptors in microbial communities is critical to electron transfer via electrical currents. These connections are facilitated through conductivity associated with various microbial aggregates. However, examination of conductivity in microbial samples is still in its relative infancy and conceptual models in terms of conductive mechanisms are still being developed and debated. The present review summarizes the fundamental understanding of electrical conductivity in microbial aggregates (e.g. biofilms, granules, consortia, and multicellular filaments) highlighting recent findings and key discoveries. A greater understanding of electrical conductivity in microbial aggregates could facilitate the survey for additional microbial communities that rely on direct extracellular electron transfer for survival, inform rational design towards the aggregates-based production of bioenergy/bioproducts, and inspire the construction of new synthetic conductive polymers.
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Affiliation(s)
- Cheng Li
- Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA
| | - Keaton Larson Lesnik
- Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA
| | - Hong Liu
- Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA.
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9
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Reverse Methanogenesis and Respiration in Methanotrophic Archaea. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2017; 2017:1654237. [PMID: 28154498 PMCID: PMC5244752 DOI: 10.1155/2017/1654237] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/11/2016] [Accepted: 10/31/2016] [Indexed: 12/21/2022]
Abstract
Anaerobic oxidation of methane (AOM) is catalyzed by anaerobic methane-oxidizing archaea (ANME) via a reverse and modified methanogenesis pathway. Methanogens can also reverse the methanogenesis pathway to oxidize methane, but only during net methane production (i.e., “trace methane oxidation”). In turn, ANME can produce methane, but only during net methane oxidation (i.e., enzymatic back flux). Net AOM is exergonic when coupled to an external electron acceptor such as sulfate (ANME-1, ANME-2abc, and ANME-3), nitrate (ANME-2d), or metal (oxides). In this review, the reversibility of the methanogenesis pathway and essential differences between ANME and methanogens are described by combining published information with domain based (meta)genome comparison of archaeal methanotrophs and selected archaea. These differences include abundances and special structure of methyl coenzyme M reductase and of multiheme cytochromes and the presence of menaquinones or methanophenazines. ANME-2a and ANME-2d can use electron acceptors other than sulfate or nitrate for AOM, respectively. Environmental studies suggest that ANME-2d are also involved in sulfate-dependent AOM. ANME-1 seem to use a different mechanism for disposal of electrons and possibly are less versatile in electron acceptors use than ANME-2. Future research will shed light on the molecular basis of reversal of the methanogenic pathway and electron transfer in different ANME types.
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10
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Stolz JF. Gaia and her microbiome. FEMS Microbiol Ecol 2016; 93:fiw247. [DOI: 10.1093/femsec/fiw247] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/03/2016] [Accepted: 12/07/2016] [Indexed: 01/09/2023] Open
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11
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Vilajeliu-Pons A, Bañeras L, Puig S, Molognoni D, Vilà-Rovira A, Hernández-del Amo E, Balaguer MD, Colprim J. External Resistances Applied to MFC Affect Core Microbiome and Swine Manure Treatment Efficiencies. PLoS One 2016; 11:e0164044. [PMID: 27701451 PMCID: PMC5049776 DOI: 10.1371/journal.pone.0164044] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 09/19/2016] [Indexed: 11/19/2022] Open
Abstract
Microbial fuel cells (MFCs) can be designed to combine water treatment with concomitant electricity production. Animal manure treatment has been poorly explored using MFCs, and its implementation at full-scale primarily relies on the bacterial distribution and activity within the treatment cell. This study reports the bacterial community changes at four positions within the anode of two almost identically operated MFCs fed swine manure. Changes in the microbiome structure are described according to the MFC fluid dynamics and the application of a maximum power point tracking system (MPPT) compared to a fixed resistance system (Ref-MFC). Both external resistance and cell hydrodynamics are thought to heavily influence MFC performance. The microbiome was characterised both quantitatively (qPCR) and qualitatively (454-pyrosequencing) by targeting bacterial 16S rRNA genes. The diversity of the microbial community in the MFC biofilm was reduced and differed from the influent swine manure. The adopted electric condition (MPPT vs fixed resistance) was more relevant than the fluid dynamics in shaping the MFC microbiome. MPPT control positively affected bacterial abundance and promoted the selection of putatively exoelectrogenic bacteria in the MFC core microbiome (Sedimentibacter sp. and gammaproteobacteria). These differences in the microbiome may be responsible for the two-fold increase in power production achieved by the MPPT-MFC compared to the Ref-MFC.
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Affiliation(s)
| | - Lluis Bañeras
- Molecular Microbial Ecology Group, Institute of Aquatic Ecology, University of Girona, Girona, Spain
- * E-mail:
| | - Sebastià Puig
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
| | - Daniele Molognoni
- Department of Civil Engineering and Architecture (D.I.C.Ar.), University of Pavia, Pavia, Italy
| | - Albert Vilà-Rovira
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
| | - Elena Hernández-del Amo
- Molecular Microbial Ecology Group, Institute of Aquatic Ecology, University of Girona, Girona, Spain
| | - Maria D. Balaguer
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
| | - Jesús Colprim
- LEQUiA, Institute of the Environment, University of Girona, Girona, Spain
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12
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Egger M, Lenstra W, Jong D, Meysman FJR, Sapart CJ, van der Veen C, Röckmann T, Gonzalez S, Slomp CP. Rapid Sediment Accumulation Results in High Methane Effluxes from Coastal Sediments. PLoS One 2016; 11:e0161609. [PMID: 27560511 PMCID: PMC4999275 DOI: 10.1371/journal.pone.0161609] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/09/2016] [Indexed: 12/04/2022] Open
Abstract
Globally, the methane (CH4) efflux from the ocean to the atmosphere is small, despite high rates of CH4 production in continental shelf and slope environments. This low efflux results from the biological removal of CH4 through anaerobic oxidation with sulfate in marine sediments. In some settings, however, pore water CH4 is found throughout the sulfate-bearing zone, indicating an apparently inefficient oxidation barrier for CH4. Here we demonstrate that rapid sediment accumulation can explain this limited capacity for CH4 removal in coastal sediments. In a saline coastal reservoir (Lake Grevelingen, The Netherlands), we observed high diffusive CH4 effluxes from the sediment into the overlying water column (0.2-0.8 mol m-2 yr-1) during multiple years. Linear pore water CH4 profiles and the absence of an isotopic enrichment commonly associated with CH4 oxidation in a zone with high rates of sulfate reduction (50-170 nmol cm-3 d-1) both suggest that CH4 is bypassing the zone of sulfate reduction. We propose that the rapid sediment accumulation at this site (~ 13 cm yr-1) reduces the residence time of the CH4 oxidizing microorganisms in the sulfate/methane transition zone (< 5 years), thus making it difficult for these slow growing methanotrophic communities to build-up sufficient biomass to efficiently remove pore water CH4. In addition, our results indicate that the high input of organic matter (~ 91 mol C m-2 yr-1) allows for the co-occurrence of different dissimilatory respiration processes, such as (acetotrophic) methanogenesis and sulfate reduction in the surface sediments by providing abundant substrate. We conclude that anthropogenic eutrophication and rapid sediment accumulation likely increase the release of CH4 from coastal sediments.
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Affiliation(s)
- Matthias Egger
- Department of Earth Sciences–Geochemistry, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Wytze Lenstra
- Department of Earth Sciences–Geochemistry, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Dirk Jong
- Department of Earth Sciences–Geochemistry, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Filip J. R. Meysman
- Department of Estuarine and Deltaic Studies, Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands
- Department of Analytical, Environmental, and Geochemistry, Vrije Universiteit Brussel, Brussels, Belgium
| | - Célia J. Sapart
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands
- Laboratoire de Glaciologie, Université Libre de Bruxelles, Brussels, Belgium
| | - Carina van der Veen
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Thomas Röckmann
- Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Santiago Gonzalez
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands
| | - Caroline P. Slomp
- Department of Earth Sciences–Geochemistry, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
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