Bleach stable and alkali-tolerant protease from Aspergillus flavus

Abstract

A strain of Aspergillus flavus which was isolated from spoilt casein produced bleach stable thermostable alkaline protease in solid state fermentation of wheat bran. Partially purified protease had optimum activity at pH 7.5 and was stable between pH 5-10. The optimum temperature of the enzyme was 50°C and at 90°C lost the activity. The addition of ionic and non-ionic detergents and surfactants to the reaction mixture enhanced the enzyme activity. The enzyme was inhibited by phenyl methyl sulphonyl fluoride.