@article {594,
	title = {Reductive precipitation of gold by dissimilatory Fe(III)-reducing bacteria and archaea.},
	journal = {Appl Environ Microbiol},
	volume = {67},
	year = {2001},
	month = {2001 Jul},
	pages = {3275-9},
	abstract = {Studies with a diversity of hyperthermophilic and mesophilic dissimilatory Fe(III)-reducing Bacteria and Archaea 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.},
	keywords = {Archaea, Bacteria, Chemical Precipitation, Ferric Compounds, Gold, Oxidation-Reduction},
	issn = {0099-2240},
	doi = {10.1128/AEM.67.7.3275-3279.2001},
	author = {Kashefi, K and Tor, J M and Nevin, K P 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}
}
