Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

STUDIES ON CHARACTERIZATION OF EXTRACELLULAR ALKALINE PROTEASE FROM A MUTANT ASPERGILLUS FLAVUS AS2

M. ROJA RANI AND N.N.PRASAD

Abstract

After our previous purificational studies on Alkaline protease from a mutant of, Aspergillus flavus AS2 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 8.5 and 550C and stable in the pH range 7.0- 8.5. The thermo stability exhibited by protease ranges from 30-500C.Among various protease inhibitors PMSF strongly inhibited the enzyme activity revealing that the enzyme in the present study is serine alkaline protease. Ca2+ 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 dehairing the goat skin after prolonged incubation. The protease showed good compatibility and stability in the presence of CaCl2 and glycine with detergents. The enzyme retained 20-40% activity with most of the detergents tested even after 3hrs. 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 3.2mgmL-1.