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ACCUMULATION AND REDUCTION OF Cr (VI) IN INDUSTRIAL EFFLUENT BY BACILLUS SP. STRAIN CrM-1

MUHAMMAD FAISAL AND SHAHIDA HASNAIN

Abstract: A Gram-positive, spore forming Bacillus sp. strain CrM^-1 was isolated from chromium-contaminated site that could resist up to 40 µg mL^-1 of K₂CrO₄ on nutrient agar and 25 µg mL^-1 in nutrient broth. The strain showed multiple heavy metals and antibiotics resistances and was able to accumulate chromate both by metabolic-dependent active uptake and energy independent passive uptake. Uptake of chromate was maximum in living cells as compared to heat-killed and dried cells. It reduced 92.25 %, 67.44 % and 25.27 % of Cr (VI) at an initial chromate concentration of 100, 500, and 1000 µg mL^-1after 24 hours with an inoculum size of 2.4⁷ cells mL^-1. Different heavy metals at low concentrations did not affect the reduction potential of the strain. The strain was able to reduce 96.66 % and 79.23 % of Cr (VI) present in industrial effluent that contained initial Cr (VI) concentration of 150 and 300 µg mL^-1, respectively.

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