Characterization Studies on Caseinolytic Extracellular Alkaline Protease from a Mutant Bacillus Licheniformis

After our previous purificational and optimisational studies on alkaline protease from a mutant of B. licheniformis Bl8, Characterisation of the purified enzyme was done from the culture supernatant by employing various parameters. The optimum pH and temperature for the activity of alkaline protease was previously found to be 10 and 50 0 C and stable in the pH range 5.0-12.0. The thermo stability exhibited by protease ranges from 30-70 0 C. Among various protease inhibitors PMSF strongly inhibited the enzyme activity revealing that the enzyme in the present study is serine alkaline protease. Ca 2+ and Mn +2 had a slight enhancing effect on the activity of the enzyme. High level of hydrolytic activity was shown by casein and also found that purified alkaline protease digested the human blood clot, coagulated egg white to soluble form and also digested the chicken skin after prolonged incubation. The protease showed good compatibility and stability in the presence of CaCl 2 and glycine with detergents. The enzyme retained 20-40% activity with most of the detergents tested even after 3 h. The supplementation of the enzyme preparation in detergents completely removed the blood stain of the cloth. The enzyme followed a typical Michaelis-Menten kinetics and the apparent km value was found to be 3.2 mg ml –1 .