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Reya Mathew, Mansura S. Mulani, and Dr. D. R. Majumder

According to various studies it has been shown that Bacillus species play a key role as biosorbent for metals. However a clear mechanism for this characteristic has not yet been deduced. It is believed that Bacillaceae family shows the property of sorption due to the presence of numerous envelopes and spores. Our studies include use of bacteria showing the capacity of producing surface layer proteins for biosorption. Copper was taken as the metal of interest and checked for its absorption. Biosorption analysis by following bacteria was carried out viz B. subtilis 2097, B. licheniformis2324, B. sphaericus2478, L. brevis 2090, L. acidophilus 2285. These cultures were obtained from NCIM. Bacillus species were grown in LB medium and Lactobacillus were grown in MRS medium. Extraction of surface layer proteins was carried out using 5M LiCl. Various parameters like culture age, pH, temperature, contact time were optimized. Comparison of biosorption by surface layer protein with that of whole cell was also studied. Maximum S layer production by B. sphaerices 2478 was found to be 38.9 in 24hrs old culture. Maximum sorption was found at pH of 7.0, temperature 370C. 500ppm of Copper Sulphate solution with 1mg of both S layer and whole cell were utilized. SDS PAGE analysis of S layer protein was performed and 40kD molecular weight for Bacillus sphaericus was visualized.