Biochemical characterization of a partially purified thermostable alkaline protease of Bacillus cereus isolated from a slaughterhouse effluent

Proteases are applicable in the leather industry but with high production costs. There is a need to produce low-cost proteases with sufficient purity for animal skin dehairing. Hence, this study extracted, partially purified, biochemically characterized and applied alkaline protease synthesized by Bacillus cereus to remove animal hair. A crude alkaline protease optimally synthesized by Bacillus cereus in skimmed milk-submerged fermentation medium was purified by glycerol precipitation and CM-Sephadex C-50. The purified enzyme was classified and the kinetic parameters were determined. The purified protease had 723.1 U/mg specific activity at 1.5 purification fold. Purified protease was stable over widely-ranging pH (3-11) and temperature (20-80 degrees C), with the highest activity at pH 7.0 and 50 degrees C. The enzyme was specific for casein, with utmost stability at 60 degrees C, and maintained most of its activity for 60 min. Na+, K+, Fe3+, and NH4+ inhibited the activity, while Ca2+ and Al3+ increased the activity. The Km and Vmax were correspondingly 4.82 mg/ml and 46.62 U/ml/min. The purified enzyme has the prospect of removing animal hair in the leather industry.