Starchy substrates for production and characterization of Bacillus subtilis amylase and its efficacy in detergent and breadmaking formulations

Utilization of starchy substrates for amylase production from Bacillus subtilis MTCC 6537 was carried out under solid state fermentation. Supplementation of beef extract and K2HPO4 to the fermentation medium increased the amylase activity to 1.6-fold. Batch scale production of amylase was also studied at 100 g and 3 kg (3 × 1 kg) tray-level batch fermentation. Extraction of fermented substrate with various salts and solvents did not show any considerable difference in amylase activity. MW of the partially purified enzyme was found to be 52 kDa by SDS–PAGE and the enzyme exhibited an optimum activity at pH 7.0 and 70°C and was stable within the pH range of 4.0–9.0 and temperatures up to 80°C. The enzyme showed maximum substrate specificity towards soluble starch. The activity was enhanced by K+ and Na+ ions, while Cu2+, Zn2+, Ni2+, and EDTA strongly inhibited the enzyme activity. The enzyme showed excellent compatibility and stability with various commercial detergents and oxidizing agents. The effect of amylase was also evaluated by the addition of some breadmaking ingredients and metabolites. The results revealed that the amylase from B. subtilis MTCC 6537 could be used as a potential candidate in detergent and breadmaking industries.