Production of bleach-stable and halo-tolerant alkaline protease by an alkalophilic Bacillus pumilus JB 05 isolated from cement industry effluents

Abstract

A new alkalophilic strain of Bacillus pumilus JB-05 producing bleach-stable and halo-tolerant alkaline protease was isolated from cement industry effluents in Karnataka, India. The effects of carbon and nitrogen sources on protease production by this alkalophilic strain were observed after a 30-h incubation. A high level of alkaline protease activity was obtained in the presence of starch as the carbon and peptone as the nitrogen sources. The partially purified enzyme showed an optimum temperature and pH activity at 58°C and 10.5, respectively. The enzyme was completely inhibited by PMSF (95.0%) indicating it as a serine protease. It is bleach-stable as it retained 35% original activity in the presence of 10% (v/v) hydrogen peroxide at 30°C after 2 h and is halo-tolerant as it retained 70% original activity in the presence of 2.5 M sodium chloride at 30C after 2 h incubation.