African Journal of Biotechnology Vol. 3 (11), pp. 610-617, November 2004          
ISSN 1684–5315 © 2004 Academic Journals

Full Length Research Paper

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

Muhammad Faisal and Shahida Hasnain*

Department of Botany, University of The Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan.

*Corresponding author. E-mail: mohdfaysal@yahoo.com.

Accepted 26 April, 2000

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.

Key words: Cr (VI) reduction, bacteria, industrial effluent, heavy metals.