Predictive approach for simultaneous biosorption of hexavalent chromium and pentachlorophenol degradation by Bacillus cereus RMLAU1

Abstract

Chromium and pentachlorophenol are the major environmental pollutants emanating from tannery effluent. Indigenous Bacillus cereus isolate was employed for biosorption and PCP degradation studies under varied environmental conditions such as pH, temperature, contact time, presence of other heavy metals, initial biosorbent and Cr⁶⁺ concentrations. Best results for Cr⁶⁺ biosorption (% removal) by living and dead biomass at 2.0 g l^-1 were found to be 35.2 mg Cr g^-1 dry wt (63%) at pH 5.0, and 42.5 mg Cr g^-1 dry wt (70.5%) at pH 4.0, respectively at 35ºC (150 rpm) during 120 min at an initial concentration of 200 mg Cr⁶⁺ l^-1 and 500 mg PCP l^-1. Among various factors, pH had profound effect on Cr⁶⁺ biosorption and PCP degradation. Maximum 7.5 % (w/v) PCP degradation ensued in 2 h only by live cells in the presence of 0.4 % (w/v) cometabolite glucose. Presumably, this is the first report on simultaneous biosorption of chromium and pentachlorophenol remediation by native Bacillus cereus isolate from tannery effluent. Statistical regressional analysis suitably validated the experimental findings. This strain would be helpful in eco-friendly simultaneous bioremediation allied with a predictive computational approach.

Key words: Bacillus cereus, Biosorption, Chromium, Heavy metals, Pentachlorophenol.