Enhanced Production of Extracellular Alkaline Protease by Bacillus cereus GVK21 by Optimized formulations

Bacillus cereus GVK21, isolated in our laboratory, is a potent producer of alkaline protease. In the present study optimization of the process and nutritional parameters is reported. Response Surface Methodology (RSM) based Box-Behnken design (BBD) was employed for the optimization of various nutritional factors such as carbon and nitrogen sources and physical parameters like incubation time, pH, temperature, inoculum size and age, agitation rate were optimized for the maximum yield of protease under submerged fermentation. The Maximum of 912 U/mL protease production was observed at 48 h of incubation, pH 9.0, 140 rpm shaking and a temperature of 40°C. Thus, with above selected process parameters the best carbon and nitrogen sources for B.cereus was found to be molasses 0.75% and Peptone 1.00%. 3D plots were generated to evaluate the damages in the response surface and to understand the relationship between the culture conditions and protease yield. The statistical optimization by RSM resulted in significant increase by about two-fold in the protease yield. The present study shows that protease production by B.cereus GVK21 is greatly influenced by cultural conditions and media constituents. This study indicates that the strain is capable to producing maximum levels of alkaline protease in a low-cost medium containing molasses and peptone as major carbon and nitrogen sources and can be exploited for industrial production of alkaline protease.