Anaerobic reduction of hexavalent chromium by bacterial cells of Achromobacter sp. Strain Ch1.
Hexavalent chromium [Cr(VI)] is a widespread environmental contaminant. Achromobacter sp. strain Chi was a Cr(VI) reducing bacterium with high reduction performance. Cr(VI) reductase was just existing in the cells, but was not discharged into the surrounding medium. Cr(VI) reduction was carried out with resting cells of strain Ch1 under anaerobic conditions. Initial pH value and lactate (electron donor) concentration were found to influence the reduction rate of Cr(VI), and the optimal conditions were at pH 9.0 and supplemented with 40 mM of lactate. The reduction rate would be constant under established conditions approximately 12.5 micromol 10(9) cells(-1) min(-1), which was not affected by cell density and initial Cr(VI) concentration. The maximal reduction capacity of Achromobacter sp. strain Ch1 was 54.2 mM, while the cell density of reduction system was 3.64 x 10(9) cells ml(-1). Energy-dispersive X-ray (EDX) analysis showed that chromium was precipitated perhaps as the form of Cr(OH)3.
Zhu
Wenjie
W
School of Metallurgical Science and Engineering, Central South University, Changsha, Hunan Province 410083, PR China.
Chai
Liyuan
L
Ma
Zemin
Z
Wang
Yunyan
Y
Xiao
Haijuan
H
Zhao
Kun
K
D042402:Achromobacter / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D002857:Chromium / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods; D007220:Industrial Waste; D010084:Oxidation-Reduction; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D018505:Waste Management / Q000379:methods*
D007220:Industrial Waste; D012989:Soil Pollutants; D002857:Chromium; C074702:chromium hexavalent ion