Microbial conversion of Cr (VI) in to Cr (III) in industrial effluent

Abstract

Bacterial strains (CrT-11, CrT-12, Bravibacterium sp. CrT-13, CrT-14) were isolated from the effluents of 
tanneries. All strains could resist very high concentration of K2CrO4 that is up to 40 mg ml-1 on nutrient 
agar and 25 mg ml-1 in nutrient broth. They have wide pH (5 to 9) and temperature (24 to 42˚C) growth 
range. They exhibited multiple metals (Ni, Zn, Mn, Cu, Co, Pb) and antibiotics (streptomycin, ampicillin, 
tetracycline, kanamycin, chloramphenicol) resistances. All the strains were able to reduce Cr (VI) in to 
Cr (III) aerobically. Bravibacterium sp. CrT-13 accumulates and reduce more Cr (VI) at all the 
concentrations applied in comparison to the other strains. These bacterial strains also take up and 
reduce Cr (VI) present in industrial effluents, and their reduction potential was not significantly affected 
in the presence of different metallic salts.