Reduction of toxic hexavalent chromium by Ochrobactrum intermedium strain SDCr-5 stimulated by heavy metals.
A Cr(VI) resistant bacterial strain SDCr-5, identified as Ochrobactrum intermedium on the basis of 16S rRNA gene sequencing, was tolerant to high concentrations of Cr(VI) up to 15 mg ml(-1) in acetate minimal medium. O. intermedium SDCr-5 reduced Cr(VI) under a wide range of concentrations from 100 to 1500 microg ml(-1) and reduction was optimum at 37 degrees C and pH 7. It reduced 200 and 721 microg ml(-1) Cr(VI) within 72 and 96 h, respectively. The rate of Cr(VI) reduction increased with concentration from 100 to 1500 microg ml(-1). The presence of heavy metal cations such as Cu(2+), Co(2+), Mn(2+) and Ni(2+) stimulated Cr(VI) reduction. Strain SDCr-5 might be useful for Cr(VI) detoxification under a wide range of environmental conditions.
Sultan
Sikander
S
Department of Botany, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan.
Hasnain
Shahida
S
D001673:Biodegradation, Environmental; D002857:Chromium / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D042041:Ochrobactrum / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D013696:Temperature
D002857:Chromium; C074702:chromium hexavalent ion