Abstract

Subtilisins (E.C.3.4.21.62) are alkaline proteases that are secreted by members of the genus Bacillus. They are serine proteases that exhibit high specific activity on proteinaceous substrates, function optimally at moderate temperatures, and are stable under alkaline conditions. Thus the use of subtilisin as an enzyme additive could help in development of quality laundry detergents. In this work the subtilisin production from Bacillus subtilis (MTCC 441) was improved by altering and optimizing the media components. This alteration was brought up by process development strategy. The effect of yeast extract, casein, peptone and sodium chloride on subtilisin production was studied and were optimized using Box Behnken Design. The optimal growth conditions for B. subtilis MTCC 441 were found to 37^oC, and pH 7.5. The optimal media composition for subtilisin production was found to be yeast extract at 6.75 g/L, peptone at 4.41 g/L, sodium chloride at 6.08 g/L, casein at 10.75 g/L with glucose at 5 g/L. The predicted and observed response were 181.00 U/mg (with desirability =0.87) and 185.70 U/mg, respectively.

Key words: Bacillus subtilis, subtilisin, Box-Behnken design, media optimization.