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 °C), with the highest activity at pH 7.0 and 50 °C. The enzyme was specific for casein, with utmost stability at 60 °C, and maintained most of its activity for 60 min. Na + , K + , Fe 3+ , and NH 4 + inhibited the activity, while Ca 2+ and Al 3+ increased the activity. The K m and V max 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. • The specific activity, yield and purification fold were recorded as 723.1 units/mg, 79% and 1.5, respectively. • Metal ions like Ca 2+ and Al 3+ increased the activity of the purified protease. • The purified protease was optimally active at pH 7 and 50 °C. • The K m and V max were 4.82 mg/ml and 46.62 units/ml/min, respectively. • The protease removed hair of animal skin, showing potential application in the leather industry.