| A strain of bacillus which could produce protease was isolated from soil sample collected from a chicken
farm, and was identified by the observation of its morphology, culture characteristics and the analysis of 16S rRNA
sequence. The properties of protease excreted by isolate fermentation were studied with different temperature, pH, metal
ion, EDTA and Tween 80. Results showed that, the isolate belonged to Bacillus amyloliquefaciens, and was named Bacillus
amyloliquefaciens strain Y-6, the optimal reaction temperature of protease produced by strain Y-6 was 55, the optimal
reaction pH was 7.0~7.5. The protease activity was steady at 40 and at pH 5.5~11, the relative enzyme activity was more
than 95% at 40 for 3 h, and was more than 90% at pH 5.5~11. The protease activity could be activated by Ca2+, Zn2+ and
Tween 80, but inhibited by Mn2+, Fe3+, Cu2+ and EDTA which had the biggest inhibition effect. |
