To study the influence of different components of fermentable substrates on induction of extracellular α-amylase synthesis by Bacillus subtilis DM-03 in solid-state fermentation and exploration of feasibility for inclusion of α-amylase in laundry detergent formulations

Study on potential of different agro-industrial waste residues for supporting alpha-amylase production by a thermophilic strain of Bacillus subtilis DM-03 in solid-state fermentation (SSF) was initiated and potato peel was found to be the best substrate for alpha-amylase production. Linear multiple regression analysis showed that higher starch contents of the fermentable substrates enhanced the alpha-amylase synthesis while the higher sugar content of the substrates imposed a negative effect presumably due to catabolic repression of the enzyme synthesis. Furthermore, C/N ratio of the substrates also played a critical role in induction of alpha-amylase synthesis. The result of batch fermentation showed 532 5 U of alpha-amylase production per gram of dry substrate by B. subtilis DM-03 post-72 h of incubation under optimized SSF condition. The crude alpha-amylase enzyme from B. subtilis DM-03 strain demonstrated excellent stability and compatibility with the laundry detergents that favors its inclusion in commercial laundry detergent formulations. (C) 2008 Elsevier B.V. All rights reserved.