Fifteen bacterium strains were isolated from soil samples and the one that had the highest proteolytic activity, from Susanoğlu 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 m length and 1 m 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 microorganism’s 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.
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