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Factors affecting microbial sulfate reduction by Desulfovibrio desulfuricans in continuous culture: Limiting nutrients and sulfide concentration
Author(s) -
Okabe S.,
Nielsen P. H.,
Characklis W. G.
Publication year - 1992
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260400612
Subject(s) - chemostat , sulfide , sulfate , chemistry , desulfovibrio , nitrogen , inorganic chemistry , nuclear chemistry , biochemistry , environmental chemistry , bacteria , biology , organic chemistry , genetics
The effects of sulfate and nitrogen concentrations of the rate and stoichiometry of microbial sulfate reduction were investigated for Desulfovibrio desulfuricans grown on lactate and sulfate in a chemostat at pH 7.0. Maximum specific growth rates (μ max ), half‐saturation coefficients ( K sul ), and cell yield ( Y c /Lac ) of 0.344 ± 0.007 and 0.352 ± 0.003 h −1 , 1.8 ± 0.3 and 1.0 ± 0.2 mg/L, and 0.020 ± 0.003 and 0.017 ± 0.003 g cell/g lactate, respectively, were obtained under sulfate‐limiting conditions at 35°C and 43°C. Maintenance energy requirements for D. desulfuricans were significant under sulfate‐limiting conditions. The extent of extracellular polymeric substance (EPS) produced was related to the carbon: nitrogen ratio in the medium. EPS production rate increased with decreased nitrogen loading rate. Nitrogen starvation also resulted in decreased cell size of D. desulfuricans . The limiting C : N ratio (w/w) for D. desulfuricans was in the range of 45 : 1 to 120 : 1. Effects of sulfide on microbial sulfate reduction, cell size, and biomass production were also ivestigated at pH 7.0. Fifty percent inhibition of lactate utilization occurred at a total sulfide concentration of approximately 500 mg/L. The cell size of D. desulfuricans decreased with increasing total sulfide concentration. Sulfide inhibition of D. desulfuricans was observed to be a reversible process. © 1992 John Wiley & Sons, Inc.