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Full-Text Articles in Life Sciences
A Genetic System For Clostridium Ljungdahlii: A Chassis For Autotrophic Production Of Biocommodities And A Model Homoacetogen, Ching Leang, Toshiyuki Ueki, Kelly Nevin, Derek R. Lovley
A Genetic System For Clostridium Ljungdahlii: A Chassis For Autotrophic Production Of Biocommodities And A Model Homoacetogen, Ching Leang, Toshiyuki Ueki, Kelly Nevin, Derek R. Lovley
Kelly Nevin
Methods for genetic manipulation of Clostridium ljungdahlii are of interest because of the potential for production of fuels and other biocommodities from carbon dioxide via microbial electrosynthesis or more traditional modes of autotrophy with hydrogen or carbon monoxide as the electron donor. Furthermore, acetogenesis plays an important role in the global carbon cycle. Gene deletion strategies required for physiological studies of C. ljungdahlii have not previously been demonstrated. An electroporation procedure for introducing plasmids was optimized, and four different replicative origins for plasmid propagation in C. ljungdahlii were identified. Chromosomal gene deletion via double-crossover homologous recombination with a suicide vector …
Improved Cathode Materials For Microbial Electrosynthesis, Tian Zhang, Huarong Nie, Timothy S. Bain, Haiyun Lu, Mengmeng Cui, Oona L. Snoeyenbos-West, Ashley E. Franks, Kelly Nevin, Thomas P. Russell, Derek R. Lovley
Improved Cathode Materials For Microbial Electrosynthesis, Tian Zhang, Huarong Nie, Timothy S. Bain, Haiyun Lu, Mengmeng Cui, Oona L. Snoeyenbos-West, Ashley E. Franks, Kelly Nevin, Thomas P. Russell, Derek R. Lovley
Kelly Nevin
Microbial electrosynthesis is a promising strategy for the microbial conversion of carbon dioxide to transportation fuels and other organic commodities, but optimization of this process is required for commercialization. Cathodes which enhance electrode–microbe electron transfer might improve rates of product formation. To evaluate this possibility, biofilms of Sporomusa ovata, which are effective in acetate electrosynthesis, were grown on a range of cathode materials and acetate production was monitored over time. Modifications of carbon cloth that resulted in a positive-charge enhanced microbial electrosynthesis. Functionalization with chitosan or cyanuric chloride increased acetate production rates 6–7 fold and modification with 3-aminopropyltriethoxysilane gave rates …
Anaerobic Benzene Oxidation By Geobacter Species, Tian Zhang, Timothy S. Bain, Kelly Nevin, Melissa A. Barlett, Derek R. Lovley
Anaerobic Benzene Oxidation By Geobacter Species, Tian Zhang, Timothy S. Bain, Kelly Nevin, Melissa A. Barlett, Derek R. Lovley
Kelly Nevin
The abundance of Geobacter species in contaminated aquifers in which benzene is anaerobically degraded has led to the suggestion that some Geobacter species might be capable of anaerobic benzene degradation, but this has never been documented. A strain of Geobacter, designated strain Ben, was isolated from sediments from the Fe(III)-reducing zone of a petroleum-contaminated aquifer in which there was significant capacity for anaerobic benzene oxidation. Strain Ben grew in a medium with benzene as the sole electron donor and Fe(III) oxide as the sole electron acceptor. Furthermore, additional evaluation of Geobacter metallireducens demonstrated that it could also grow in benzene-Fe(III) …
Interspecies Electron Transfer Via H2 And Formate Rather Than Direct Electrical Connections In Co-Cultures Of Pelobacter Carbinolicus And Geobacter Sulfurreducens, Amelia-Elena Rotaru, Pravin M. Shrestha, Fanghua Liu, Toshiyuki Ueki, Kelly Nevin, Zarath M. Summers, Derek R. Lovley
Interspecies Electron Transfer Via H2 And Formate Rather Than Direct Electrical Connections In Co-Cultures Of Pelobacter Carbinolicus And Geobacter Sulfurreducens, Amelia-Elena Rotaru, Pravin M. Shrestha, Fanghua Liu, Toshiyuki Ueki, Kelly Nevin, Zarath M. Summers, Derek R. Lovley
Kelly Nevin
Direct interspecies electron transfer (DIET) is an alternative to interspecies H2/formate transfer as a mechanism for microbial species to cooperatively exchange electrons during syntrophic metabolism. To understand what specific properties contribute to DIET, studies were conducted with Pelobacter carbinolicus, a close relative of Geobacter metallireducens, which is capable of DIET. P. carbinolicus grew in co-culture with Geobacter sulfurreducens with ethanol as electron donor and fumarate as electron acceptor, conditions under which G. sulfurreducens formed direct electrical connections with G. metallireducens. In contrast to the cell aggregation associated with DIET, P. carbinolicus and G. sulfurreducens did not aggregate. Attempts to initiate …
Promoting Direct Interspecies Electron Transfer With Activated Carbon, Fanghua Liu, Amelia-Elena Rotaru, Pravin M. Shrestha, Nikhil S. Malvankar, Kelly Nevin, Derek R. Lovley
Promoting Direct Interspecies Electron Transfer With Activated Carbon, Fanghua Liu, Amelia-Elena Rotaru, Pravin M. Shrestha, Nikhil S. Malvankar, Kelly Nevin, Derek R. Lovley
Kelly Nevin
Granular activated carbon (GAC) is added to methanogenic digesters to enhance conversion of wastes to methane, but the mechanism(s) for GAC's stimulatory effect are poorly understood. GAC has high electrical conductivity and thus it was hypothesized that one mechanism for GAC stimulation of methanogenesis might be to facilitate direct interspecies electron transfer (DIET) between bacteria and methanogens. Metabolism was substantially accelerated when GAC was added to co-cultures of Geobacter metallireducens and Geobacter sulfurreducens grown under conditions previously shown to require DIET. Cells were attached to GAC, but did not aggregate as they do when making biological electrical connections between cells. …
Electrical Conductivity In A Mixed-Species Biofilm, Nikhil S. Malvankar, Joanne Lau, Kelly Nevin, Ashley E. Franks, Mark T. Tuominen, Derek R. Lovley
Electrical Conductivity In A Mixed-Species Biofilm, Nikhil S. Malvankar, Joanne Lau, Kelly Nevin, Ashley E. Franks, Mark T. Tuominen, Derek R. Lovley
Kelly Nevin
Geobacter sulfurreducens can form electrically conductive biofilms, but the potential for conductivity through mixed species biofilms has not been examined. A current-producing biofilm grown from a wastewater sludge inoculum was highly conductive with low charge transfer resistance even though microorganisms other than Geobacteraceae accounted for nearly half the microbial community.
Electrosynthesis Of Organic Compounds From Carbon Dioxide Catalyzed By A Diversity Of Acetogenic Microorganisms, Derek Lovley, Kelly P. Nevin, Sarah A. Hensley, Ashley E. Franks, Zarath M. Summers, Jianhong Ou, Trevor L. Woodard, Oona L. Snoeyenbos-West
Electrosynthesis Of Organic Compounds From Carbon Dioxide Catalyzed By A Diversity Of Acetogenic Microorganisms, Derek Lovley, Kelly P. Nevin, Sarah A. Hensley, Ashley E. Franks, Zarath M. Summers, Jianhong Ou, Trevor L. Woodard, Oona L. Snoeyenbos-West
Kelly Nevin
Microbial electrosynthesis, a process in which microorganisms use electrons derived from electrodes to reduce carbon dioxide to multi-carbon, extracellular organic compounds, is a potential strategy for capturing electrical energy in carbon-carbon bonds of readily stored and easily distributed products, such as transportation fuels. To date, only one organism, the acetogen, Sporomusa ovata, has been shown to be capable of electrosynthesis. The purpose of this study was to determine if a wider range of microorganisms might be capable of this process. Several other acetogenic bacteria, including two other Sporomusa species, Clostridium ljungdahlii, Clostridium aceticum, and Moorella thermoacetica consumed current with the …
Microbial Fuel Cells, A Current Review, Ashley E. Franks, Kelly Nevin
Microbial Fuel Cells, A Current Review, Ashley E. Franks, Kelly Nevin
Kelly Nevin
Microbial fuel cells (MFCs) are devices that can use bacterial metabolism to produce an electrical current from a wide range organic substrates. Due to the promise of sustainable energy production from organic wastes, research has intensified in this field in the last few years. While holding great promise only a few marine sediment MFCs have been used practically, providing current for low power devices. To further improve MFC technology an understanding of the limitations and microbiology of these systems is required. Some researchers are uncovering that the greatest value of MFC technology may not be the production of electricity but …
Anode Biofilm Transcriptomics Reveals Outer Surface Components Essential For High Density Current Production In Geobacter Sulfurreducens Fuel Cells, Derek Lovley, Kelly P. Nevin, Byoung-Chan Kim, Richard H. Glaven, Jessica P. Johnson, Trevor L. Woodard, Barbara A. Methѐ, Raymond J. Didonato Jr., Sean F. Covalla, Ashley E. Franks, Anna Liu
Anode Biofilm Transcriptomics Reveals Outer Surface Components Essential For High Density Current Production In Geobacter Sulfurreducens Fuel Cells, Derek Lovley, Kelly P. Nevin, Byoung-Chan Kim, Richard H. Glaven, Jessica P. Johnson, Trevor L. Woodard, Barbara A. Methѐ, Raymond J. Didonato Jr., Sean F. Covalla, Ashley E. Franks, Anna Liu
Kelly Nevin
The mechanisms by which Geobacter sulfurreducens transfers electrons through relatively thick (>50 µm) biofilms to electrodes acting as a sole electron acceptor were investigated. Biofilms of Geobacter sulfurreducens were grown either in flow-through systems with graphite anodes as the electron acceptor or on the same graphite surface, but with fumarate as the sole electron acceptor. Fumarate-grown biofilms were not immediately capable of significant current production, suggesting substantial physiological differences from current-producing biofilms. Microarray analysis revealed 13 genes in current-harvesting biofilms that had significantly higher transcript levels. The greatest increases were for pilA, the gene immediately downstream of pilA, and …
Graphite Electrode As A Sole Electron Donor For Reductive Dechlorination Of Tetrachlorethene By Geobacter Lovleyi, Sarah M. Strycharz, Trevor L. Woodard, Jessica P. Johnson, Kelly P. Nevin, Robert A. Stanford, Frank E. Lӧffler, Derek Lovley
Graphite Electrode As A Sole Electron Donor For Reductive Dechlorination Of Tetrachlorethene By Geobacter Lovleyi, Sarah M. Strycharz, Trevor L. Woodard, Jessica P. Johnson, Kelly P. Nevin, Robert A. Stanford, Frank E. Lӧffler, Derek Lovley
Kelly Nevin
The possibility that graphite electrodes can serve as the direct electron donor for microbially catalyzed reductive dechlorination was investigated with Geobacter lovleyi. In an initial evaluation of whether G. lovleyi could interact electronically with graphite electrodes, cells were provided with acetate as the electron donor and an electrode as the sole electron acceptor. Current was produced at levels that were ca. 10-fold lower than those previously reported for Geobacter sulfurreducens under similar conditions, and G. lovleyi anode biofilms were correspondingly thinner. When an electrode poised at −300 mV (versus a standard hydrogen electrode) was provided as the electron donor, G. …
Lack Of Electricity Production By Pelobacter Carbinolicus Indicates That The Capacity For Fe(Iii) Oxide Reduction Does Not Necessarily Confer Electron Transfer Ability To Fuel Cell Anodes, Hanno Richter, Martin Lanthier, Kelly P. Nevin, Derek Lovley
Lack Of Electricity Production By Pelobacter Carbinolicus Indicates That The Capacity For Fe(Iii) Oxide Reduction Does Not Necessarily Confer Electron Transfer Ability To Fuel Cell Anodes, Hanno Richter, Martin Lanthier, Kelly P. Nevin, Derek Lovley
Kelly Nevin
The ability of Pelobacter carbinolicus to oxidize electron donors with electron transfer to the anodes of microbial fuel cells was evaluated because microorganisms closely related to Pelobacter species are generally abundant on the anodes of microbial fuel cells harvesting electricity from aquatic sediments. P. carbinolicus could not produce current in a microbial fuel cell with electron donors which support Fe(III) oxide reduction by this organism. Current was produced using a coculture of P. carbinolicus and Geobacter sulfurreducens with ethanol as the fuel. Ethanol consumption was associated with the transitory accumulation of acetate and hydrogen. G. sulfurreducens alone could not metabolize …
Geonomic And Microarray Analysis Of Aromatics Degradation In Geobacter Metallireducens And Compan To A Geobacter Isolate From A Contaminated Fieldriso Site, Derek Lovley, Jessica E. Butler, Qiang He, Kelly P. Nevin, Zhili He, Jizhong Zhou
Geonomic And Microarray Analysis Of Aromatics Degradation In Geobacter Metallireducens And Compan To A Geobacter Isolate From A Contaminated Fieldriso Site, Derek Lovley, Jessica E. Butler, Qiang He, Kelly P. Nevin, Zhili He, Jizhong Zhou
Kelly Nevin
Background: Groundwater and subsurface environments contaminated with aromatic compounds can be remediated in situ by Geobacter species that couple oxidation of these compounds to reduction of Fe(III)-oxides. Geobacter metallireducens metabolizes many aromatic compounds, but the enzymes involved are not well known. Results: The complete G. metallireducens genome contained a 300 kb island predicted to encode enzymes for the degradation of phenol, p-cresol, 4-hydroxybenzaldehyde, 4-hydroxybenzoate, benzyl alcohol, benzaldehyde, and benzoate. Toluene degradation genes were encoded in a separate region. None of these genes was found in closely related species that cannot degrade aromatic compounds. Abundant transposons and phage-like genes in the …
Role Of Red Gsu In Stress Response And Fe(Iii) Reduction In Geobacter Sulfurreducens, Laurie N. Didonato, Sara A. Sullivan, Barbara A. Methѐ, Kelly P. Nevin, Reg England, Derek Lovley
Role Of Red Gsu In Stress Response And Fe(Iii) Reduction In Geobacter Sulfurreducens, Laurie N. Didonato, Sara A. Sullivan, Barbara A. Methѐ, Kelly P. Nevin, Reg England, Derek Lovley
Kelly Nevin
Geobacter species are key members of the microbial community in many subsurface environments in which dissimilatory metal reduction is an important process. The genome of Geobacter sulfurreducens contains a gene designated relGsu, which encodes a RelA homolog predicted to catalyze both the synthesis and the degradation of guanosine 3′,5′-bispyrophosphate (ppGpp), a regulatory molecule that signals slow growth in response to nutrient limitation in bacteria. To evaluate the physiological role of RelGsu in G. sulfurreducens, a relGsu mutant was constructed and characterized, and ppGpp levels were monitored under various conditions in both the wild-type and relGsu mutant strains. In the wild-type …
Biofilm And Nanowire Production Leads To Increased Current In Geobacter Sulfurreducens Fuel Cells, Gemma Reguera, Kelly P. Nevin, Julie S. Nicoll, Sean F. Covalla, Trevor L. Woodard, Derek Lovley
Biofilm And Nanowire Production Leads To Increased Current In Geobacter Sulfurreducens Fuel Cells, Gemma Reguera, Kelly P. Nevin, Julie S. Nicoll, Sean F. Covalla, Trevor L. Woodard, Derek Lovley
Kelly Nevin
Geobacter sulfurreducens developed highly structured, multilayer biofilms on the anode surface of a microbial fuel cell converting acetate to electricity. Cells at a distance from the anode remained viable, and there was no decrease in the efficiency of current production as the thickness of the biofilm increased. Genetic studies demonstrated that efficient electron transfer through the biofilm required the presence of electrically conductive pili. These pili may represent an electronic network permeating the biofilm that can promote long-range electrical transfer in an energy-efficient manner, increasing electricity production more than 10-fold.
Potential For Quantifying Expression Of The Geobacteraceae Citrate Synthase Gene To Assess The Activity Of Geobacteraceae In The Subsurface And On Current-Harvesting Electrodes, Dawn E. Holmes, Kelly P. Nevin, Regina A. O'Neil, Joy E. Ward, Lorrie A. Adams, Trevor L. Woodard, Helen A. Vrionis, Derek Lovley
Potential For Quantifying Expression Of The Geobacteraceae Citrate Synthase Gene To Assess The Activity Of Geobacteraceae In The Subsurface And On Current-Harvesting Electrodes, Dawn E. Holmes, Kelly P. Nevin, Regina A. O'Neil, Joy E. Ward, Lorrie A. Adams, Trevor L. Woodard, Helen A. Vrionis, Derek Lovley
Kelly Nevin
The Geobacteraceae citrate synthase is phylogenetically distinct from those of other prokaryotes and is a key enzyme in the central metabolism of Geobacteraceae. Therefore, the potential for using levels of citrate synthase mRNA to estimate rates of Geobacter metabolism was evaluated in pure culture studies and in four different Geobacteraceae-dominated environments. Quantitative reverse transcription-PCR studies with mRNA extracted from cultures of Geobacter sulfurreducens grown in chemostats with Fe(III) as the electron acceptor or in batch with electrodes as the electron acceptor indicated that transcript levels of the citrate synthase gene, gltA, increased with increased rates of growth/Fe(III) reduction or current …
Adaptation To Disruption Of The Electron Transfer Pathway For Fe(Iii) Reduction In Geobacter Sulfurreducens, Ching Leang, Lorrie A. Adams, Kuk-Jeong Chin, Kelly P. Nevin, Barbara A. Methѐ, Jennifer Webster, Manju L. Sharma, Derek Lovley
Adaptation To Disruption Of The Electron Transfer Pathway For Fe(Iii) Reduction In Geobacter Sulfurreducens, Ching Leang, Lorrie A. Adams, Kuk-Jeong Chin, Kelly P. Nevin, Barbara A. Methѐ, Jennifer Webster, Manju L. Sharma, Derek Lovley
Kelly Nevin
Previous studies demonstrated that an outer membrane c-type cytochrome, OmcB, was involved in Fe(III) reduction in Geobacter sulfurreducens. An OmcB-deficient mutant was greatly impaired in its ability to reduce both soluble and insoluble Fe(III). Reintroducing omcB restored the capacity for Fe(III) reduction at a level proportional to the level of OmcB production. Here, we report that the OmcB-deficient mutant gradually adapted to grow on soluble Fe(III) but not insoluble Fe(III). The adapted OmcB-deficient mutant reduced soluble Fe(III) at a rate comparable to that of the wild type, but the cell yield of the mutant was only ca. 60% of that …
Dna Microarray Analysis Of Nitrogen Fixation And Fe(Iii) Reduction In Geobacter Sulfurreducens, Jennifer Webster, Barbara A. Methé, Kelly P. Nevin, Jessica E. Butler, Derek Lovley
Dna Microarray Analysis Of Nitrogen Fixation And Fe(Iii) Reduction In Geobacter Sulfurreducens, Jennifer Webster, Barbara A. Methé, Kelly P. Nevin, Jessica E. Butler, Derek Lovley
Kelly Nevin
A DNA microarray representing the genome of Geobacter sulfurreducens was constructed for use in global gene expression profiling of cells under steady-state conditions with acetate as the electron donor and Fe(III) or fumarate as the electron acceptor. Reproducible differences in transcript levels were also observed in comparisons between cells grown with ammonia and those fixing atmospheric nitrogen. There was a high correlation between changes in transcript levels determined with microarray analyses and an evaluation of a subset of the genome with quantitative PCR. As expected, cells required to fix nitrogen had higher levels of transcripts of genes associated with nitrogen …
In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley
In Situ Expression Of Nigd In Geobacteraceae In Subsurface Sediments, Dawn E. Holmes, Kelly P. Nevin, Derek Lovley
Kelly Nevin
In order to determine whether the metabolic state of Geobacteraceae involved in bioremediation of subsurface sediments might be inferred from levels of mRNA for key genes, in situ expression of nifD, a highly conserved gene involved in nitrogen fixation, was investigated. When Geobacter sulfurreducens was grown without a source of fixed nitrogen in chemostats with acetate provided as the limiting electron donor and Fe(III) as the electron acceptor, levels of nifD transcripts were 4 to 5 orders of magnitude higher than in chemostat cultures provided with ammonium. In contrast, the number of transcripts of recA and the 16S rRNA gene …
Isolation, Characterization, And U(Vi)-Reducing Potential Of A Facultatively Anaerobic, Acid-Resistant Bacterium From Low-Ph, Nitrate- And U(Vi) Contaminated Subsurface Sediment And Description Of Salmonella Subterranea Sp.Nov., Evgenya S. Shelobolina, Sara A. Sullivan, Kathleen R. O'Neil, Kelly P. Nevin, Derek Lovley
Isolation, Characterization, And U(Vi)-Reducing Potential Of A Facultatively Anaerobic, Acid-Resistant Bacterium From Low-Ph, Nitrate- And U(Vi) Contaminated Subsurface Sediment And Description Of Salmonella Subterranea Sp.Nov., Evgenya S. Shelobolina, Sara A. Sullivan, Kathleen R. O'Neil, Kelly P. Nevin, Derek Lovley
Kelly Nevin
A facultatively anaerobic, acid-resistant bacterium, designated strain FRCl, was isolated from a low-pH, nitrate- and U(VI)-contaminated subsurface sediment at site FW-024 at the Natural and Accelerated Bioremediation Research Field Research Center in Oak Ridge, Tenn. Strain FRCl was enriched at pH 4.5 in minimal medium with nitrate as the electron acceptor, hydrogen as the electron donor, and acetate as the carbon source. Clones with 16S ribosomal DNA (rDNA) sequences identical to the sequence of strain FRCl were also detected in a U(VI)-reducing enrichment culture derived from the same sediment. Cells of strain FRCl were gram-negative motile regular rods 2.0 to …
Microorganisms Associated With Uranium Bioremediation In A High Salinity Subsurface Sediment, Kelly P. Nevin, Kevin T. Finneran, Derek Lovley
Microorganisms Associated With Uranium Bioremediation In A High Salinity Subsurface Sediment, Kelly P. Nevin, Kevin T. Finneran, Derek Lovley
Kelly Nevin
Although stimulation of dissimilatory metal reduction to promote the reductive precipitation of uranium has been shown to successfully remove uranium from some aquifer sediments, the organisms in the family Geobacteraceae that have been found to be associated with metal reduction in previous studies are not known to grow at the high salinities found in some uranium-contaminated groundwaters. Studies with a highly saline uranium-contaminated aquifer sediment demonstrated that the addition of acetate could stimulate the removal of U(VI) from the groundwater. This removal was associated with an enrichment in microorganisms most closely related to Pseudomonas and Desulfosporosinus species.
Mechanisms For Accessing Insoluble Fe(Iii) Oxide During Dissimilatory Fe(Iii) Reduction By Geothrix Fermentans, Kelly P. Nevin, Derek Lovley
Mechanisms For Accessing Insoluble Fe(Iii) Oxide During Dissimilatory Fe(Iii) Reduction By Geothrix Fermentans, Kelly P. Nevin, Derek Lovley
Kelly Nevin
Mechanisms for Fe(III) oxide reduction were investigated in Geothrix fermentans, a dissimilatory Fe(III)-reducing microorganism found within the Fe(III) reduction zone of subsurface environments. Culture filtrates of G. fermentans stimulated the reduction of poorly crystalline Fe(III) oxide by washed cell suspensions, suggesting that G. fermentans released one or more extracellular compounds that promoted Fe(III) oxide reduction. In order to determine if G. fermentans released electron-shuttling compounds, poorly crystalline Fe(III) oxide was incorporated into microporous alginate beads, which prevented contact between G. fermentans and the Fe(III) oxide. G. fermentans reduced the Fe(III) within the beads, suggesting that one of the compounds that …
Reductive Presipitation Of Gold By Dissimilatory Fe(Iii)-Reducing Bacteria And Archaea, Kazem Kashefi, Jason M. Tor, Kelly P. Nevin, Derek Lovley
Reductive Presipitation Of Gold By Dissimilatory Fe(Iii)-Reducing Bacteria And Archaea, Kazem Kashefi, Jason M. Tor, Kelly P. Nevin, Derek Lovley
Kelly Nevin
Studies with a diversity of hyperthermophilic and mesophilic dissimilatory Fe(III)-reducing Bacteria andArchaea demonstrated that some of these organisms are capable of precipitating gold by reducing Au(III) to Au(0) with hydrogen as the electron donor. These studies suggest that models for the formation of gold deposits in both hydrothermal and cooler environments should consider the possibility that dissimilatory metal-reducing microorganisms can reductively precipitate gold from solution.
Lack Of Production Of Electron-Shuttling Compounds Or Solubilization Of Fe(Iii) During Reduction Of Insoluble Fe(Iii) Oxide Of Geobacter Metallireducens, Derek Lovley, Kelly P. Nevin
Lack Of Production Of Electron-Shuttling Compounds Or Solubilization Of Fe(Iii) During Reduction Of Insoluble Fe(Iii) Oxide Of Geobacter Metallireducens, Derek Lovley, Kelly P. Nevin
Kelly Nevin
Studies with the dissimilatory Fe(III)-reducing microorganism Geobacter metallireducens demonstrated that the common technique of separating Fe(III)-reducing microorganisms and Fe(III) oxides with semipermeable membranes in order to determine whether the Fe(III) reducers release electron-shuttling compounds and/or Fe(III) chelators is invalid. This raised doubts about the mechanisms for Fe(III) oxide reduction by this organism. However, several experimental approaches indicated that G. metallireducens does not release electron-shuttling compounds and does not significantly solubilize Fe(III) during Fe(III) oxide reduction. These results suggest that G. metallireducens directly reduces insoluble Fe(III) oxide.