Extraction and purification of a highly thermostable alkaline caseinolytic protease from wastes Penaeus vannamei suitable for food and detergent industries

A novel thermostable protease was purified from Penaeus vannamei from Persian Gulf to homogeneity level using ammonium sulfate precipitation and anion-exchange chromatography. The purified protease showed a single band on native and SDS-PAGE with a molecular weight of 24 kDa on SDS-PAGE. The enzyme showed the broad highest catalytic activity for hydrolysis of the substrate with maximal activity at pH 7 and 80 °C. Activity of the enzyme was inhibited by Hg2+, Zn2+ Co2+ and Cu2+, while protease activity was increased in the presence of Fe2+ and Mn2+ by factors of 173% and 102%, respectively. Enzyme shows a broad substrate specificity and hydrolyzes both natural and synthetic substrates. Based on the Michaelis-Menten plots, the Km with casein as substrate was 16.8 μM and Vmax was 82.6 μM/min. The enzyme, derived from L. vannamei, possesses unique characteristics and could be used in various industrial and biotechnological applications.