@article {486,
	title = {Characterization of extracellular minerals produced during dissimilatory Fe(III) and U(VI) reduction at 100 degrees C by Pyrobaculum islandicum.},
	journal = {Geobiology},
	volume = {6},
	year = {2008},
	month = {2008 Mar},
	pages = {147-54},
	abstract = {In order to gain insight into the significance of biotic metal reduction and mineral formation in hyperthermophilic environments, metal mineralization as a result of the dissimilatory reduction of poorly crystalline Fe(III) oxide, and U(VI) reduction at 100 degrees C by Pyrobaculum islandicum was investigated. When P. islandicum was grown in a medium with poorly crystalline Fe(III) oxide as an electron acceptor and hydrogen as an electron donor, the Fe(III) oxide was reduced to an extracellular, ultrafine-grained magnetite with characteristics similar to that found in some hot environments and that was previously thought to be of abiotic origin. Furthermore, cell suspensions of P. islandicum rapidly reduced the soluble and oxidized form of uranium, U(VI), to extracellular precipitates of the highly insoluble U(IV) mineral, uraninite (UO(2)). The reduction of U(VI) was dependent on the presence of hydrogen as the electron donor. These findings suggest that microbes may play a key role in metal deposition in hyperthermophilic environments and provide a plausible explanation for such phenomena as magnetite accumulation and formation of uranium deposits at ca. 100 degrees C.},
	keywords = {Ferric Compounds, Ferumoxytol, Hot Temperature, Hydrogen, Minerals, Oxidation-Reduction, Pyrobaculum, Uranium, X-Ray Diffraction},
	issn = {1472-4669},
	doi = {10.1111/j.1472-4669.2007.00142.x},
	author = {Kashefi, K and Moskowitz, B M and Lovley, D R}
}
@article {614,
	title = {Reduction of Fe(III), Mn(IV), and toxic metals at 100 degrees C by Pyrobaculum islandicum.},
	journal = {Appl Environ Microbiol},
	volume = {66},
	year = {2000},
	month = {2000 Mar},
	pages = {1050-6},
	abstract = {It has recently been noted that a diversity of hyperthermophilic microorganisms have the ability to reduce Fe(III) with hydrogen as the electron donor, but the reduction of Fe(III) or other metals by these organisms has not been previously examined in detail. When Pyrobaculum islandicum was grown at 100 degrees C in a medium with hydrogen as the electron donor and Fe(III)-citrate as the electron acceptor, the increase in cell numbers of P. islandicum per mole of Fe(III) reduced was found to be ca. 10-fold higher than previously reported. Poorly crystalline Fe(III) oxide could also serve as the electron acceptor for growth on hydrogen. The stoichiometry of hydrogen uptake and Fe(III) oxide reduction was consistent with the oxidation of 1 mol of hydrogen resulting in the reduction of 2 mol of Fe(III). The poorly crystalline Fe(III) oxide was reduced to extracellular magnetite. P. islandicum could not effectively reduce the crystalline Fe(III) oxide minerals goethite and hematite. In addition to using hydrogen as an electron donor for Fe(III) reduction, P. islandicum grew via Fe(III) reduction in media in which peptone and yeast extract served as potential electron donors. The closely related species P. aerophilum grew via Fe(III) reduction in a similar complex medium. Cell suspensions of P. islandicum reduced the following metals with hydrogen as the electron donor: U(VI), Tc(VII), Cr(VI), Co(III), and Mn(IV). The reduction of these metals was dependent upon the presence of cells and hydrogen. The metalloids arsenate and selenate were not reduced. U(VI) was reduced to the insoluble U(IV) mineral uraninite, which was extracellular. Tc(VII) was reduced to insoluble Tc(IV) or Tc(V). Cr(VI) was reduced to the less toxic, less soluble Cr(III). Co(III) was reduced to Co(II). Mn(IV) was reduced to Mn(II) with the formation of manganese carbonate. These results demonstrate that biological reduction may contribute to the speciation of metals in hydrothermal environments and could account for such phenomena as magnetite accumulation and the formation of uranium deposits at ca. 100 degrees C. Reduction of toxic metals with hyperthermophilic microorganisms or their enzymes might be applied to the remediation of metal-contaminated waters or waste streams.},
	keywords = {Chromium, Cobalt, Energy Metabolism, Ferric Compounds, Geological Phenomena, Geology, Iron, Manganese, Metals, Heavy, Oxidation-Reduction, Technetium, Thermoproteaceae, Uranium, Water Pollutants, Chemical},
	issn = {0099-2240},
	author = {Kashefi, K and Lovley, D R}
}
@article {641,
	title = {Bioremediation of organic and metal contaminants with dissimilatory metal reduction.},
	journal = {J Ind Microbiol},
	volume = {14},
	year = {1995},
	month = {1995 Feb},
	pages = {85-93},
	abstract = {Dissimilatory metal reduction has the potential to be a helpful mechanism for both intrinsic and engineered bioremediation of contaminated environments. Dissimilatory Fe(III) reduction is an important intrinsic process for removing organic contaminants from aquifers contaminated with petroleum or landfill leachate. Stimulation of microbial Fe(III) reduction can enhance the degradation of organic contaminants in ground water. Dissimilatory reduction of uranium, selenium, chromium, technetium, and possibly other metals, can convert soluble metal species to insoluble forms that can readily be removed from contaminated waters or waste streams. Reduction of mercury can volatilize mercury from waters and soils. Despite its potential, there has as yet been limited applied research into the use of dissimilatory metal reduction as a bioremediation tool.},
	keywords = {Bacteria, Biodegradation, Environmental, Chromium, Hydrocarbons, Iron, Mercury, Metals, Oxidation-Reduction, Selenium, Uranium},
	issn = {0169-4146},
	author = {Lovley, D R}
}
@article {647,
	title = {Reduction of uranium by cytochrome c3 of Desulfovibrio vulgaris.},
	journal = {Appl Environ Microbiol},
	volume = {59},
	year = {1993},
	month = {1993 Nov},
	pages = {3572-6},
	abstract = {The mechanism for U(VI) reduction by Desulfovibrio vulgaris (Hildenborough) was investigated. The H2-dependent U(VI) reductase activity in the soluble fraction of the cells was lost when the soluble fraction was passed over a cationic exchange column which extracted cytochrome c3. Addition of cytochrome c3 back to the soluble fraction that had been passed over the cationic exchange column restored the U(VI)-reducing capacity. Reduced cytochrome c3 was oxidized by U(VI), as was a c-type cytochrome(s) in whole-cell suspensions. When cytochrome c3 was combined with hydrogenase, its physiological electron donor, U(VI) was reduced in the presence of H2. Hydrogenase alone could not reduce U(VI). Rapid U(VI) reduction was followed by a subsequent slow precipitation of the U(IV) mineral uraninite. Cytochrome c3 reduced U(VI) in a uranium-contaminated surface water and groundwater. Cytochrome c3 provides the first enzyme model for the reduction and biomineralization of uranium in sedimentary environments. Furthermore, the finding that cytochrome c3 can catalyze the reductive precipitation of uranium may aid in the development of fixed-enzyme reactors and/or organisms with enhanced U(VI)-reducing capacity for the bioremediation of uranium-contaminated waters and waste streams.},
	keywords = {Biotransformation, Chemical Precipitation, Cytochrome c Group, Desulfovibrio vulgaris, Oxidation-Reduction, Uranium, Water Pollutants, Radioactive},
	issn = {0099-2240},
	author = {Lovley, D R and Widman, P K and Woodward, J C and Phillips, E J}
}
@article {655,
	title = {Reduction of uranium by Desulfovibrio desulfuricans.},
	journal = {Appl Environ Microbiol},
	volume = {58},
	year = {1992},
	month = {1992 Mar},
	pages = {850-6},
	abstract = {The possibility that sulfate-reducing microorganisms contribute to U(VI) reduction in sedimentary environments was investigated. U(VI) was reduced to U(IV) when washed cells of sulfate-grown Desulfovibrio desulfuricans were suspended in a bicarbonate buffer with lactate or H2 as the electron donor. There was no U(VI) reduction in the absence of an electron donor or when the cells were killed by heat prior to the incubation. The rates of U(VI) reduction were comparable to those in respiratory Fe(III)-reducing microorganisms. Azide or prior exposure of the cells to air did not affect the ability of D. desulfuricans to reduce U(VI). Attempts to grow D. desulfuricans with U(VI) as the electron acceptor were unsuccessful. U(VI) reduction resulted in the extracellular precipitation of the U(IV) mineral uraninite. The presence of sulfate had no effect on the rate of U(VI) reduction. Sulfate and U(VI) were reduced simultaneously. Enzymatic reduction of U(VI) by D. desulfuricans was much faster than nonenzymatic reduction of U(VI) by sulfide, even when cells of D. desulfuricans were added to provide a potential catalytic surface for the nonenzymatic reaction. The results indicate that enzymatic U(VI) reduction by sulfate-reducing microorganisms may be responsible for the accumulation of U(IV) in sulfidogenic environments. Furthermore, since the reduction of U(VI) to U(IV) precipitates uranium from solution, D. desulfuricans might be a useful organism for recovering uranium from contaminated waters and waste streams.},
	keywords = {Biodegradation, Environmental, Desulfovibrio, Kinetics, Oxidation-Reduction, Sulfates, Uranium, X-Ray Diffraction},
	issn = {0099-2240},
	author = {Lovley, D R and Phillips, E J}
}
