Biochemical properties of extracellular protease from Staphylococcus epidermidis isolated from Harbin dry sausages and its hydrolysis of meat protein

Abstract

This study aimed to explore biochemical properties of extracellular protease from Staphylococcus (S.) epidermidis BP9 isolated from Harbin dry sausages and its future potential application in Harbin dry sausages. The protease was purified by 80% ammonium sulfate, ion exchange, and gel filtration chromatography to obtain a 24 kDa extracellular protease. The protease reached maximal activity at pH 6.0 and 50 °C and was stable at pH 4.0–9.0 and 20–40 °C. Its protease activity was inhibited in the presence of Fe2+. The enzymatic characterization of the protease revealed a Vmax 62.5 U/mL·min, Km 11.76 mg/mL, and the half-life = 62.44 min, ΔH*d = 72.11 kJ/mol, ΔG*d = 91.40 kJ/mol, and ΔS*d = −59.60 J/mol·K at 50 °C. In addition, the protease hydrolysed myofibrillar protein into small particles and produced soluble peptides. This study provides a basis for understanding the biochemical characteristics of the S. epidermidis BP9 protease and its future application for Harbin dry sausages.