Production of an amylase from newly Bacillus strain: Optimization by response-surface methodology, characterization...

Using the statistical approaches, the optimization of amylase production by a newly Bacillus strain was achieved. Keeping the insignificant factor at lower levels and following the optimized condition (inoculum size 0.3; 19 h of incubation; 18 g L^-1 of starch; 4 g L^-1 of MgSO₄; and 15 g L^-1 NaCl) the amylase activity has reached 18.48 ± 0.42 U mL^-1 with an improvement factor of 6.48-fold-times. The properties of the crude amylase, tentatively named AmySBM, were examined, revealing an optimal activity at 60 °C and pH 7. The enzyme demonstrated good stability across a wide temperature range (40-60 °C) and pH levels (6-7). Its activity depended on the presence of Ca²⁺. Additionally, it was discovered that maltose was the sole product of starch hydrolysis by AmySBM, an encouraging result for introducing it into bread making. Tests on dough properties with varied amylase amounts revealed that 0.06 U g^-1 was ideal, with white flour producing the greatest results. Incorporating Rhizopus oryzae lipase at 1.2 U g^-1 dramatically increased bread quality. Finally, combining an enzymatic cocktail of AmySBM and lipase at optimal quantities improved the qualities of white bread, demonstrating its potential as an anti-staling agent to replace conventional improvers in the baking industry.