Studies on Purification and Characterisation of Caseinolytic Extracellular Alkaline Protease from a Mutant Alkalophillic Bacillus Licheniformis B18

Abstract

Alkaline protease from a mutant of B. licheniformis Bl8 was purified from the culture supernatant by employing different
methods such as ammonium sulphate precipitation, DEAE cellulose chromatography followed by Gel filtration using
Sephadex G-100. The yield of the enzyme after purification was found to be 10%. Protease was found to be homogenouswhen examined by SDS-PAGE and the enzyme showed that it has a molecular weight of 28 KDa. Characterization studieswere carried out using the purified enzyme. While the optimum pH and temperature for the activity of alkaline proteasewas found to be 10 and 500C and stable in the pH range 5.0 – 12.0. The thermo stability exhibited by protease ranges from30-700C. Among various protease inhibitors PMSF strongly inhibited the enzyme activity revealing that the enzyme in thepresent study is serine alkaline protease