Characteristics of protease produced by Bacillus subtilis PCA 20-3 isolated from Korean traditional meju

摘要

Protease production and its characteristics were investigated with Bacillus subtilis PCA20-3 which was isolated from Korean traditional meju. The optimum culture conditions of Bacillus subtilis PCA20-3 for the production of the protease were as follow: 0.2 percent soytone, 2 percent starch, 0.1 percent (NH_4)_2SO_4, 0.2 percent CaCl_2, 0.01 percent yeast extract, 0.1 percent K_2HPO_4, 0.1 percent KH_2PO_4, pH 7.0, 30 deg C and 20 hrs. The optimum pH and temperature for enzyme activity of protease producing Bacillus subtilis PCA20-3 were pH 8.0-10.0 and 55 deg C, respectively. The enzyme was relatively stable at pH 6.0-11.0 and at temperature below 50 deg C. The activity of the enzyme was inhibited by Fe~(2+) and Cu~(2+) 2 mM phenymethanesulfonyl fluoride inhibited 89.2 percent of enzyme activity. This indicates that the enzyme is serine protease. The K_m value was 5 X 10~(-4) M, V_(max) value was 100 #mu#g/min. This enzyme hydrolyzed casein more rapidly than bovine serum albumin.