Cr(VI) resistance and reduction in Shewanella alga, strain bry

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:210351

Caccavo, F Jr; McInerney, M J ^[1]

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1. Univ. of Oklahoma, Norman, OK (United States)

The dissimilatory metal-reducing microorganism Shewanella alga strain BrY was used to study dissimilatory Cr(VI) reduction, Strain BrY produced a terminal reductase which could reduce Cr(VI), but Cr(VI) was toxic to this organism under growth conditions. A Cr(VI)-resistant mutant was isolated by exposing BrY to gradually increasing concentrations of Cr(VI). This mutant, designated strain BrY-MT, had a minimum inhibitory concentration of 8 mM Cr(VI),which was 30 fold greater than that of strain BrY. The Cr(VI)-sensitive strain BrY took up 2.4 times more {sup 51}CrO{sub 4}{sup 2-} than the Cr(VI)-resistant strain BrY-MT. The initial rate of {sup 51}CrO{sub 4}{sup 2-} uptake by BrY was 41.3 pmol/min./mg protein, while the intial rate of {sup 51}CrO{sub 4}{sup 2-} uptake by strain BrY-MT was 9.92 pmol/min/mg protein. Aerobic growth of either BrY or BrY-MT in the presence of Cr(VI) was enhanced by the addition of SO{sub 4}{sup 2-} and inhibited by the addition of djenkolic acid. BrY-MT produced an active Cr(VI) reductase, but did not reduce Cr(VI) under aerobic conditions. Strain BrY-MT gained energy to support anaerobic growth by coupling the oxidation of lactate to the reduction of Cr(VI), It is the first organism shown to grow with Cr(VI) as the sole terminal electron acceptor, and thus may be a useful organism for Cr(VI) bioremediation.

• OSTI ID: 210351
• Report Number(s): CONF-9509139--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ANAEROBIC DIGESTION
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MUTATIONS
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