Chromate/Nitrite Interactions in Shewanella Oneidensis MR-1: Evidence for Multiple Cr(VI) Reduction Mechanisms Dependent on Physiological Growth Conditions

Journal Article · Sat Jun 01 04:00:00 EDT 2002 · Bioengineering & Biotechnology

OSTI ID:912074

Apel, William Arnold; Viamajala, S; Peyton, Brent Michael; Petersen, J N

Inhibition of hexavalent chromium [Cr(VI)] reduction due to nitrate and nitrite was observed during tests with Shewanella oneidensis MR-1 (previously named Shewanella putrefaciens MR-1 and henceforth referred to as MR-1). Initial Cr(VI) reduction rates were measured at various nitrite concentrations, and a mixed inhibition kinetic model was used to determine the kinetic parameters-maximum Cr(VI) reduction rate and inhibition constant [V(max,Cr(VI)) and K(i,Cr(VI))]. Values of V(max,Cr(VI)) and K(i,Cr(VI)) obtained with MR-1 cultures grown under denitrifying conditions were observed to be significantly different from the values obtained when the cultures were grown with fumarate as the terminal electron acceptor. It was also observed that a single V(max,Cr(VI)) and K(i,Cr(VI)) did not adequately describe the inhibition kinetics of either nitrate-grown or fumarate-grown cultures. The inhibition patterns indicate that Cr(VI) reduction in MR-1 is likely not limited to a single pathway, but occurs via different mechanisms some of which are dependent on growth conditions. Inhibition of nitrite reduction due to the presence of Cr(VI) was also studied, and the kinetic parameters V(max,NO2) and K(i,NO2) were determined. It was observed that these coefficients also differed significantly between MR-1 grown under denitrifying conditions and fumarate reducing conditions. The inhibition studies suggest the involvement of nitrite reductase in Cr(VI) reduction. Because nitrite reduction is part of the anaerobic respiration process, inhibition due to Cr(VI) might be a result of interaction with the components of the anaerobic respiration pathway such as nitrite reductase. Also, differences in the degree of inhibition of nitrite reduction activity by chromate at different growth conditions suggest that the toxicity mechanism of Cr(VI) might also be dependent on the conditions of growth. Cr(VI) reduction has been shown to occur via different pathways, but to our knowledge, multiple pathways within a single organism leading to Cr(VI) reduction has not been reported previously.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 912074
• Report Number(s): INEEL/JOU-01-01069
• Journal Information: Bioengineering & Biotechnology, Journal Name: Bioengineering & Biotechnology Journal Issue: 7 Vol. 78
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
BINDING ENERGY
CHROMATES
CHROMIUM
ELECTRONS
KINETICS
NITRATES
NITRITES
OXIDOREDUCTASES
RESPIRATION
Shewanella oneidensis
TOXICITY
VALENCE
conditions
growth
hexavalent chromium