Seed cultures were prepared by transferring a loop of lawn from the fully grown slant into a 250 mL flask containing 50 mL of MLB medium and incubated at 30C on a rotary shaker at 150 rpm for 36 h. 0.5 mL of this precultured fluid was inoculated in 250 mL Erlenmeyer flask containing 50 mL of main culture medium with the following composition (%): Tryptone 1, KH2PO4 0.05, MgSO47H2O 0.03; CaCl2 2H2O 0.1; NaCl 0.1; and glycerol 10.0 mL. The initial pH of the medium was adjusted to 7.0 by 1 N NaOH or 1 N HCl. Main culture medium was maintained at the same conditions for 48 h. The cells or cell debris were removed by centrifugation at 10,000 g and at 4C for 10 min. Supernatants were harvested as crude protease. All experiments were triplicated and the standard deviation was within 5%