Production, Partial Purification, and Biochemical Characterization of a Thermotolerant Alkaline Metallo-protease from...

Protease-producing Staphylococcus sciuri was isolated from poultry soil samples and culture conditions for protease production were optimized. The isolated protease showed a maximum activity of 235.1 U/ml. Enzyme purification procedure involved ammonium sulphate precipitation and Sephacryl S-200 HR gel filtration chromatography (GFC). The purification process resulted in the production of three protease fractions namely protease І (metallo-alkaline protease), II, and IІІ. The metallo-alkaline protease was purified to 25.49-fold with specific activity of 982.22 U/mg and 3.76% recovery. The partially purified metallo-protease was optimally active at pH 10.0 and 70 °C and exhibited thermal stability up to 50 °C. The protease activity was enhanced by Ca²⁺ and Mg²⁺, completely inhibited by Hg²⁺ and Cu²⁺, and significantly reduced by EDTA. The protease showed significant stability towards various surfactants, including SDS. The K_m and V_max values were 0.68 mg/ml and 166.66 nmol of azocasein/ml/h, respectively, while the activation energy (E_a) was 3.07 Kcal/mol. Hence, it is evident that the produced protease possesses unique characteristics and could be a plausible candidate for various industrial and biotechnological applications.