Optimized production and properties of thermostable alkaline protease from Bacillus subtilis SHS-04 grown on groundnut (Arachis hypogaea) meal

Production of alkaline protease from Bacillus subtilis SHS-04 was investigated under different fermentation conditions involving low-cost substrates with the aim of optimizing yield of enzyme. Maximum enzyme production (1616.21 U/mL) was achieved using groundnut meal (0.75%) as nitrogen source and 0.5% glucose as carbon source at 48 h cultivation period, pH 9, 45 ° C and 200 rpm. The yield was 348% increase over comparable control samples. The alkaline protease had optimum temperature of 60 ° C and remarkably exhibited 80% relative activity at 70 ° C. It was highly thermostable showing 98.7% residual activity at 60 ° C after 60 minutes of incubation at pH 9.0 and was stable in the presence of organic solvents studied. These properties indicate the viability of the protease for biotechnological and industrial applications. The optimized yield of enzyme achieved in this study establishes groundnut meal as potential low-cost substrate for alkaline protease production by B. subtilis SHS-04.