Full Length Research Paper Isolation of protease producing novel Bacillus cereus and detection of optimal conditions
Fifteen bacterium strains were isolated from soil samples and the one that had the highest proteolytic activity, from Susano.lu village at Silifke-Mersin, was selected. The strain was identified and determined as Bacillus cereus. The bacterium, that had R type colony morphology, subterminal spores, motile and facultative anaerobe microorganism, was a gram positive with 10 ƒÊ length and 1 ƒÊ width. It could ferment glucose, fructose and maltose which formed acid but not gas. Catalase and urease were positive. The bacterium could grow on common medium easily and form b-haemolyze on blood agar. It was determined that the microorganismfs growth continued up to the 12th hour and when it gets to the 18th hour, it was in a stationary phase. As a result, after the 18th hour, it was in a lytic phase. The optimum growth temperature range was 20 - 40‹C and the optimum pH range was 6.0 . 10.0, respectively. Maximum growth was obtained at 30‹C and at pH 7.0. The highest protease activity was determined at 30‹C temperature and 6.4 pH conditions and after the 18th hour, it decreased evidently.
Key words: Protease, production, optimization, Bacillus sp.