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Title: Bacterial chromate reduction and product characterization

Abstract

Bacillus subtilis reduced hexavalent chromate to trivalent chromium under either aerobic or anaerobic conditions. Reduction of CR(VI) and appearance of extracellular Cr(III) were demonstrated by electron spin resonance and spectrophotometry. Chromate reduction was stimulated more than five-fold by freeze-thawing, indicating that intracellular reductases or chemical reductants reduce chromate more rapidly than do intact cells. Moderately concentrated cells (10% pellet volume after centrifugation) reduced approximately 40 {mu}M chromate/min (2 mg Cr/1-min) when exposed to 100 {mu}M chromate (5 mg Cr/1). Highly concentrated cells (70% pellet volume) reduced more than 99.8% of 2 mM chromate (100 mg Cr/1) within 15 min. This rate of chromate reduction was of the same order of magnitude as the rate of respiration in aerobic cells. A substantial fraction of the reduction product (ca. 75%) was extracellular Cr(M), which could readily be separated from the cells by centrifugation. At high chromate concentrations, some fraction of reduced CR(VI) appeared to be taken up by cells, consistent with a detection of intracellular paramagnetic products. At low chromate concentrations, undefined growth medium alone reduced Cr(VI), but at a slow rate, relative to cells. Under appropriate conditions, B. subtilis appears to be an organism of choice for detoxifying chromate-contaminated soil andmore » water.« less

Authors:
 [1]; ;  [2]
  1. Lawrence Berkeley Lab., CA (United States)
  2. California Univ., Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley Lab., CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10130983
Report Number(s):
LBL-33252; WSRC-MS-93-018; CONF-930482-4
ON: DE93007698; TRN: 93:006367
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: 2. international symposium on in situ and on-site bioreclamation,San Diego, CA (United States),5-8 Apr 1993; Other Information: PBD: Nov 1992
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 54 ENVIRONMENTAL SCIENCES; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; CHROMATES; REDUCTION; BIODEGRADATION; SOIL CHEMISTRY; LAND POLLUTION; BACILLUS SUBTILIS; REMEDIAL ACTION; OXIDOREDUCTASES; 550500; 320305; 540220; 053003; METABOLISM; INDUSTRIAL WASTE MANAGEMENT; CHEMICALS MONITORING AND TRANSPORT; CHEMICAL AND THERMAL EFFLUENTS

Citation Formats

Mehlhorn, R J, Buchanan, B B, and Leighton, T. Bacterial chromate reduction and product characterization. United States: N. p., 1992. Web.
Mehlhorn, R J, Buchanan, B B, & Leighton, T. Bacterial chromate reduction and product characterization. United States.
Mehlhorn, R J, Buchanan, B B, and Leighton, T. 1992. "Bacterial chromate reduction and product characterization". United States. https://www.osti.gov/servlets/purl/10130983.
@article{osti_10130983,
title = {Bacterial chromate reduction and product characterization},
author = {Mehlhorn, R J and Buchanan, B B and Leighton, T},
abstractNote = {Bacillus subtilis reduced hexavalent chromate to trivalent chromium under either aerobic or anaerobic conditions. Reduction of CR(VI) and appearance of extracellular Cr(III) were demonstrated by electron spin resonance and spectrophotometry. Chromate reduction was stimulated more than five-fold by freeze-thawing, indicating that intracellular reductases or chemical reductants reduce chromate more rapidly than do intact cells. Moderately concentrated cells (10% pellet volume after centrifugation) reduced approximately 40 {mu}M chromate/min (2 mg Cr/1-min) when exposed to 100 {mu}M chromate (5 mg Cr/1). Highly concentrated cells (70% pellet volume) reduced more than 99.8% of 2 mM chromate (100 mg Cr/1) within 15 min. This rate of chromate reduction was of the same order of magnitude as the rate of respiration in aerobic cells. A substantial fraction of the reduction product (ca. 75%) was extracellular Cr(M), which could readily be separated from the cells by centrifugation. At high chromate concentrations, some fraction of reduced CR(VI) appeared to be taken up by cells, consistent with a detection of intracellular paramagnetic products. At low chromate concentrations, undefined growth medium alone reduced Cr(VI), but at a slow rate, relative to cells. Under appropriate conditions, B. subtilis appears to be an organism of choice for detoxifying chromate-contaminated soil and water.},
doi = {},
url = {https://www.osti.gov/biblio/10130983}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Nov 01 00:00:00 EST 1992},
month = {Sun Nov 01 00:00:00 EST 1992}
}

Conference:
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