Mechanisms of extracellular electron transfer in anaerobic methanotrophic archaea

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Feb. 17, 2024

Abstract Anaerobic methanotrophic (ANME) archaea are environmentally important, uncultivated microorganisms that oxidize the potent greenhouse gas methane. During methane oxidation, ANME engage in extracellular electron transfer (EET) with other microbes, metal oxides, and electrodes through unclear mechanisms. Here, we cultivate ANME-2d ( ‘Ca . Methanoperedens’) bioelectrochemical systems observe strong methane-dependent current (91–93% of total current) associated high enrichment ‘ Ca Methanoperedens’ on anode (up to 82% community), as determined by metagenomics transmission microscopy. Electrochemical metatranscriptomic analyses suggest EET mechanism is similar at various electrode potentials, possible involvement an uncharacterized short-range transport protein complex OmcZ nanowires.

Language: Английский

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Investigation of acetate uptake kinetics of mature Geobacter sulfurreducens biofilms in continuous bioelectrochemical systems reveals unexpected challenges

Bioelectrochemistry, Journal Year: 2025, Volume and Issue: unknown, P. 108978 - 108978

Published: March 1, 2025

Mature Geobacter sulfurreducens biofilms cultivated at two distinct anode potentials, representing unlimited and limited electron acceptor availability, were subjected to different acetate concentrations in a continuous reactor system. The Nernst-Michaelis-Menten equation, being modified consider the conditions of stirred-tank reactor, was applied analyze uptake kinetics. For first time, kinetics pure G. based on quantification consumption determined. Acetate parameters (KM,Ac = 1.41 ± 0.42 mM, vmax,Ac 1.10 0.12 mmolAc- h-1 gDW-1, n 4) obtained from cultivation 0.4 V (vs. SHE), showed significant differences compared an approach that derived current production. This deviation is likely related coulombic efficiency, which exhibited dependence concentration. efficiency 30-50 % for <1 saturated 78.6 4.0 more than 2 mM acetate. Despite equation developed cover limiting terminal conditions, its application -0.1 yielded contradictory results indicating limits. Considering complexity plasticity together with complex extracellular transfer machinery, are model system shown provide unexpected challenges demanding highly controlled experimental conditions.

Language: Английский

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Decoupled respiration in electro-active bacteria

Communications Biology, Journal Year: 2025, Volume and Issue: 8(1)

Published: May 2, 2025

Studies on electron-transfer pathways in certain bacterial strains have revealed that the degree of coupling electron transfer to proton translocation along respiratory chain can be regulated according metabolic demands. This first line response, based existence energy dissipation mechanisms, has not been demonstrated a general pattern across kingdom, let alone operative electro-active bacteria. In this study, we hypothesized cells should respond over-polarization by also triggering decoupling mechanisms prevent overloads. Based electrochemical analyses, propose recently discovered inner-membrane cytochrome CbcBA - used Geobacter sulfurreducens bacteria for cellular respiration near thermodynamic energetic limit act as an gate when metabolism is demanded, contributing regulate balance cell carbon assimilation from electrode respiration.

Language: Английский

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Low electrode potentials enhance current generation by Geobacter sulfurreducens biofilms: A high-throughput study

Biosensors and Bioelectronics, Journal Year: 2025, Volume and Issue: 276, P. 117232 - 117232

Published: Feb. 12, 2025

Language: Английский

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The role of CsrA in controls the extracellular electron transfer and biofilm production in Geobacter sulfurreducens

Frontiers in Microbiology, Journal Year: 2025, Volume and Issue: 16

Published: March 11, 2025

CsrA is a post-transcriptional regulator that controls biofilm formation, virulence, carbon metabolism, and motility, among other phenotypes in bacteria. has been extensively studied γ-proteobacteria firmicutes, However the cellular processes controlled for regulation δ-proteobacteria remain unknown. In this work, we constructed characterized Δ csrA mutant strain Geobacter sulfurreducens to determine involvement of protein extracellular electron transfer. The shows higher rates insoluble Fe(III) reduction than wild type using acetate as donor growth with fumarate soluble (Fe(III)) was similar type. Biofilm quantification characterization by confocal laser scanning microscopy, showed produces up twice much more 95% viable cells. Transcriptome analysis RNA-seq biofilms developed on an inert support, differentially expressed 244 genes (103 upregulated 141 downregulated), including those related transfer, exopolysaccharide synthesis, c-di-GMP synthesis degradation. To validate transcriptome data, RT-qPCR confirmed differential expression several selected strain. Also, current production microbial fuel cells performed produced 45–50% identify changed graphite electrodes MFC, 181 their biofilms, which 113 were only MFC 68 well grown glass. silico 5′-UTR regions revealed 76 have consensus sequence binding. our knowledge first report describing transfer member δ-proteobacteria.

Language: Английский

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Impact of extended starvation conditions on bioelectrocatalytic activity of a methane-producing microbial electrolysis cell

Bioresource Technology, Journal Year: 2024, Volume and Issue: unknown, P. 131491 - 131491

Published: Sept. 1, 2024

Language: Английский

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A survey of the Desulfuromonadia “cytochromome” provides a glimpse of the unexplored diversity of multiheme cytochromes in nature

BMC Genomics, Journal Year: 2024, Volume and Issue: 25(1)

Published: Oct. 20, 2024

Multiheme cytochromes c (MHC) provide prokaryotes with a broad metabolic versatility that contributes to their role in the biogeochemical cycling of elements and energy production bioelectrochemical systems. However, MHC have only been isolated studied detail from limited number species. Among these, Desulfuromonadia spp. are particularly MHC-rich. To obtain view diversity MHC, we employed bioinformatic tools study cytochromome encoded genomes class.

Language: Английский

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Global transcriptional analysis of Geobacter sulfurreducens gsu1771 mutant biofilm grown on two different support structures

PLoS ONE, Journal Year: 2023, Volume and Issue: 18(10), P. e0293359 - e0293359

Published: Oct. 25, 2023

Electroactive biofilms formation by the metal-reducing bacterium Geobacter sulfurreducens is a step crucial for bioelectricity generation and bioremediation. The transcriptional regulator GSU1771 controls expression of essential genes involved in electron transfer biofilm G. sulfurreducens, with GSU1771-deficient producing thicker more electroactive biofilms. Here, RNA-seq analyses were conducted to compare global gene patterns wild-type Δgsu1771 mutant grown on non-conductive (glass) conductive (graphite electrode) materials. glass surface exhibited 467 differentially expressed (DE) (167 upregulated 300 downregulated) versus biofilm. In contrast, graphite electrode 119 DE (79 40 Among these genes, 67 also (56 same regulation 11 exhibiting counter-regulation). biofilms, we identified potential target exopolysaccharide synthesis (gsu1961-63, gsu1959, gsu1972-73, gsu1976-77). RT-qPCR then confirm differential selection interest. DNA-protein binding assays demonstrated direct promoter region pgcA, pulF, relA, gsu3356. Furthermore, heme-staining western blotting revealed an increase c-type cytochromes including OmcS OmcZ Collectively, our findings that extracellular which electroconductive development.

Language: Английский

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Influence of support materials on the electroactive behavior, structure and gene expression of wild type and GSU1771-deficient mutant of Geobacter sulfurreducens biofilms

Environmental Science and Pollution Research, Journal Year: 2024, Volume and Issue: unknown

Published: May 17, 2024

Abstract Geobacter sulfurreducens DL1 is a metal-reducing dissimilatory bacterium frequently used to produce electricity in bioelectrochemical systems (BES). The biofilm formed on electrodes one of the most important factors for efficient electron transfer; this possible due production type IV pili and c- cytochromes that allow it carry out extracellular transfer (EET) final acceptors. In study, we analyzed different support materials (glass, hematite (Fe 2 O 3 ) glass, fluorine-doped tin oxide (FTO) semiconductor Fe FTO, graphite, stainless steel) by G. (WT) GSU1771-deficient strain mutant (Δ gsu1771 ). GSU1771 transcriptional regulator controls expression several genes involved transfer. Different approaches experimental tests were carried with biofilms grown including structure analysis confocal laser scanning microscopy (CLSM), characterization electrochemical activity, quantification relative gene RT-qPCR. selected EET was analyzed, observing an overexpression pgcA , omcS omcM omcF from Δ compared those WT, also epsH gene, which exopolysaccharide synthesis. Although observed Δgsu1771 strain, associated redox processes are similar WT more current produced, think could be higher certain exopolysaccharides despite chemical environment where develops. This study supports capable adapting grows.

Language: Английский

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Geobacter sulfurreducens’ Unique Metabolism Results in Cells with a High Iron and Lipid Content

Microbiology Spectrum, Journal Year: 2022, Volume and Issue: 10(6)

Published: Oct. 27, 2022

Geobacter sulfurreducens is a ubiquitous iron-reducing bacterium in soils, and engineered systems, it can respire an electrode to produce measurable electric current. Its unique metabolism, heavily dependent on extensive network of cytochromes, requires cell composition. In this work, we used metallomics, fraction elemental analyses, transcriptomics study analyze the composition G. sulfurreducens. Elemental studies (C, H, O, N, ash content) showed high C:O H:O ratios approximately 1.7:1 0.25:1, indicative more reduced that consistent with lipid content. Our shows cells have large amount iron (2 ± 0.2 μg/g dry weight) lipids (32 0.5% weight/dry does not change whether are grown soluble or insoluble electron acceptor. The concentration, higher than similar microorganisms, attributed production cytochromes abundant transcriptomic analyses both solid acceptor growth. must be considered when growing microorganism for lab commercial applications. IMPORTANCE electroactive microorganism. nature, grows metallic minerals by transferring electrons them, effectively "breathing" metals. manmade system, respires It has become model organism organisms. There potential biotechnological applications bridge gap between biology electrical signal and, as reducer soils around world, impact global cycle. We measured concentrations metals, macromolecules, basic elements define organism's also gene expression data discuss which proteins those metals could associated with. found compared other bacteria-these observations important future microbiologists biotechnologists working organism.

Language: Английский

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