Engineering of the α-Amylase From Geobacillus stearothermophilus US100 for Detergent Incorporation

AmyUS100 Delta IG is a variant of the most thermoactive and thermostable maltohexaose forming alpha-amylase produced by Geobacillus stearothermophilus sp.US100. This enzyme which was designed to improve the thermostability 4 the wild-type enzyme has acquired a very high resistance to chelator agents. According to modeling structural studies and with the aim of enhancing its resistance towards chemical oxidation, a mutant (AmyUS100 Delta IG/M197A) was created by substituting methionine 197 to alanine. The catalytic proprieties of the resulting mutant show alterations in the specific activity and the profile of starch hydrolysis. Interestingly, AmyUS100 Delta IG/M197A displayed the highest resistance to oxidation compared to the AmyUS100 Delta IG and to Termamyl300 (R), the well-known commercial amylase used in detergent. Further, performance of the engineered alpha-amylase was estimated in the presence of commonly used detergent compounds and a wide range of commercial detergent (liquid and solid). These studies indicated a high compatibility and performance of ArnyUS100 Delta IG/M197A, Suggesting its potential application in detergent industry.