Abstract: Protease-producing bacteria were isolated from traditional shrimp sauce by using casein agar medium containing 10% NaCl. Based on its morphological, biochemical and molecular properties, Virgibacillus sp. P-4 was determined as target strain for further study. The strain grew best at 30–37 ℃ with a salinity of 5%–15%. The protease produced by Virgibacillus sp. P-4 showed the optimum activity at 40 ℃, and was stable in the range of 20–50 ℃. The enzymatic activity reached its peak when NaCl concentration was 15%. Besides, Virgibacillus sp. P-4 might produce more than one extracellular protease except sulfhydryl protease. According to the rate of release of free amino acids, the protease might preferably hydrolyze peptides containing Phe-, Tyr-, Lys-, His-, Pro- and Leu-.

Key words: protease-producing bacteria, halophilic bacteria, shrimp sauce, properties