摘要：In this study, extracellular proteases of some Bacillus species were investigated. 12 Bacillus sp . were firstly tested with agar and broth media maximum total protease activities (TPA) were showed by B. cereus and S. subtilis and these bacteria were used for protease production 5 different broth media were prepared for this purpose. Among the media, maximum activities were obtained from a modification of FC broth medium. After 48 hours incubation time at 37 oC, TPA from B. cereus on FC broth medium was obtained about 600 U/ml at 9.0-10.0 pH range. At the same conditions, B. subtilis protease showed 525 U/ml activity at pH 7.0-8.0. Effects of various concentrations of ZnSO4 and EDTA on crude protease solutions were detected. The protease activity of B. subtilis was inhibited about 65% with 200 mM EDTA but this activity could be reactivated with 0.2 mM ZnSO4. These agent didn’t very much inhibit the protease activity of B. cereus . These results indicated that B. subtilis protease was a metalloprotease but B. cereus protease was not. The enzyme protein in crude enzyme solutions were partially recovered. B. cereus protease was isolated up to 49% and B. subtilis protease was isolated up to 47%.
