Effective bioremediation of chromium(VI) by a bacterial consortium for decontamination of Industrial effluents using low-cost substrates.

Abstract

Low-cost substrates are promising substitutes for bioprocesses that can impact microbial metabolism. In the present study Banana peel extract (BPE) medium as a fermentation medium was compared to commercial optimized LB medium for bacterial consortia (Bacillus cereus SBS1 and Bacillus thuringiensis SBS3) for optimization of Cr (VI) bioremediation. Plackett-Burman design was utilized for optimization of factors, where ammonium chloride, inoculum size, sodium chloride and pH showed significant effects on Cr (VI) reduction. Commercial medium was optimized with 1% NH₄Cl, 0. 7% yeast extract, 0. 3% NaCl, and 2% dextrose) and physical parameters (pH-7.0, temperature-37 °C). The growth of bacteria and percentage of Cr (VI) reduction were analyzed. The Cr (VI) reduction was 80% in BPE medium which was 60% in commercial modified LB medium. The strains optimized in BPE medium when employed for the treatment of industrial effluents in a 5 lt bioreactor showed 90% Cr (VI) reduction. BPE can serve as a suitable medium for effective Cr (VI)) bio reduction at bioreactor level and provide a cost effective and eco-friendly alternative for large scale bioremediation of industrial effluents.