Biosorption of Lead by Bacillus cereus Isolated from Industrial Effluents

Aims: To study the biosorption of lead ions from solution using Bacillus cereus isolated from industrial effluents collected from Peenya industrial area, Bangalore, India and to determine the optimum conditions for biosorption. Study design: Experimental study. Place and Duration of Study: Department of Microbiology and Biotechnology, Bangalore University, Bangalore, Karnataka, India, between October 2008 and December 2009. Methodology: Sixty bacterial strains were isolated from industrial effluents collected from Peenya industrial area. Among the sixty isolates only six were selected for further investigation due to their high minimum inhibition concentration for lead. Lead biosorption studies were carried out for all the six isolates using atomic absorption spectrometry. The optimum conditions (temperature, pH and culture age) for biosorption were determined for the isolate showing highest lead biosorption. Results: The lead biosorption capability of all six isolates was studied at different concentrations of lead (100, 200, 300, 400 and 500 mg/l). The isolate 6 showed highest lead biosorption capability and was identified as Bacillus cereus. Studies on the control of environmental factors revealed that an optimum temperature of 30°C and pH 5, facilitates maximum biosorption of lead by 24hrs old culture of Bacillus cereus. Conclusion: Biosorption is an alternative to traditional physicochemical methods for removing toxic metals from wastewaters. The results of this study are discussed in the light of the biosorption capacity of Bacillus cereus that could be exploited in the bioremediation of lead.