Bioremediation of chromium in tannery effluent by microbial consortia

Chromium is the most toxic and common among the heavy metal pollutants of industrial effluents. In the present work the chromium remediation ability of Bacillus subtilis, Pseudomonas aeruginosa and Saccharomyces cerevisiae in consortia and in their immobilized forms was studied and their efficiencies were compared. Flame Atomic Absorption Spectroscopy and diphenyl carbazide method was used to quantify chromium in the effluent. The chromium content of the effluent was around 770 mg/l before remediation, after which it reduced to 5.2 - 5.7 mg/l. The best activity was observed by S. cerevisiae - P. aeruginosa consortia, followed by immobilized beads of S. cerevisiae and S. cerevisiae - B. subtilis consortia.