Kinetics of a hydrogen-oxidizing, perchlorate-reducing bacterium.
This paper provides the first kinetic parameters for a hydrogen-oxidizing perchlorate-reducing bacterium (PCRB), Dechloromonas sp. PC1. The qmax for perchlorate and chlorate were 3.1 and 6.3 mg/mgDW-day, respectively. The K for perchlorate was 0.14 mg/L, an order of magnitude lower than reported for other PCRB. The yields Y on perchlorate and chlorate were 0.23 and 0.22 mgDW/mg, respectively, and the decay constant b was 0.055/day. The growth-threshold, Smin, for perchlorate was 14 microg/L, suggesting that perchlorate cannot be reduced below this level when perchlorate is the primary electron-acceptor, although it may be possible when oxygen or nitrate is the primary acceptor. Chlorate accumulated at maximum concentrations of 0.6-4.3 mg/L in batch tests with initial perchlorate concentrations ranging from 100 to 600 mg/L. Furthermore, 50 mg/L chlorate inhibited perchlorate reduction with perchlorate at 100 mg/L. This is the first report of chlorate accumulation and inhibition for a pure culture of PCRB. These Chlorate effects are consistent with competitive inhibition between perchlorate and chlorate for the (per)chlorate reductase enzyme.
Nerenberg
Robert
R
Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208-3109, USA. nerenberg.1@nd.edu
Kawagoshi
Yasunori
Y
Rittmann
Bruce E
BE
D001419:Bacteria / Q000378:metabolism*; D001483:Base Sequence; D017931:DNA Primers; D006859:Hydrogen / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D010472:Perchlorates / Q000378:metabolism*
D017931:DNA Primers; D010472:Perchlorates; D006859:Hydrogen