Isolation of protease producing novel Bacillus cereus and detection of optimal conditions

Ozgur K., Nilufer C.

AFRICAN JOURNAL OF BIOTECHNOLOGY, cilt.10, sa.7, ss.1160-1164, 2011 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 10 Konu: 7
  • Basım Tarihi: 2011
  • Sayfa Sayıları: ss.1160-1164


Fifteen bacterium strains were isolated from soil samples and the one that had the highest proteolytic activity, from Susanoglu 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 mu length and 1 mu 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 beta-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 degrees C and the optimum pH range was 6.0 - 10.0, respectively. Maximum growth was obtained at 30 degrees C and at pH 7.0. The highest protease activity was determined at 30 degrees C temperature and 6.4 pH conditions and after the 18th hour, it decreased evidently.