Life Sciences Commons^™

Growth Of Thermophilic And Hyperthermophilic Fe(Iii)-Reducing Microorganisms On A Ferruginous Smectite As The Sole Electron Acceptor, Derek Lovley, Kazem Kashefi, Evgenya S. Shelobolina, W. Crawford Elliott

Derek Lovley

Recent studies have suggested that the structural Fe(III) within phyllosilicate minerals, including smectite and illite, is an important electron acceptor for Fe(III)-reducing microorganisms in sedimentary environments at moderate temperatures. The reduction of structural Fe(III) by thermophiles, however, has not previously been described. A wide range of thermophilic and hyperthermophilic Archaea and Bacteria from marine and freshwater environments that are known to reduce poorly crystalline Fe(III) oxides were tested for their ability to reduce structural (octahedrally coordinated) Fe(III) in smectite (SWa-1) as the sole electron acceptor. Two out of the 10 organisms tested, Geoglobus ahangari and Geothermobacterium ferrireducens, were not able …

Genomics 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

Derek Lovley

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 …

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

Derek Lovley

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 …

Importance Of C-Type Cytochromes For U(Vi) Reduction By Geobacter Sulfurreducens, Evgenya S. Shelobolina, Maddalena V. Coppi, Anton A. Korenevsky, Laurie N. Didonato, Sara A. Sullivan, Hiromi Konishi, Huifang Xu, Ching Leang, Jessica E. Butler, Byoung-Chan Kim, Derek Lovley

Derek Lovley

Background In order to study the mechanism of U(VI) reduction, the effect of deleting c-type cytochrome genes on the capacity of Geobacter sulfurreducens to reduce U(VI) with acetate serving as the electron donor was investigated. Results The ability of several c-type cytochrome deficient mutants to reduce U(VI) was lower than that of the wild type strain. Elimination of two confirmed outer membrane cytochromes and two putative outer membrane cytochromes significantly decreased (ca. 50–60%) the ability of G. sulfurreducens to reduce U(VI). Involvement in U(VI) reduction did not appear to be a general property of outer membrane cytochromes, as elimination of …