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

Kebabcı Ö.

African Journal Of Biotechnology, vol.10, no.7, pp.1160-1164, 2011 (Journal Indexed in SCI Expanded)

  • Publication Type: Article / Article
  • Volume: 10 Issue: 7
  • Publication Date: 2011
  • Title of Journal : African Journal Of Biotechnology
  • Page Numbers: pp.1160-1164


Fifteen bacterium strains were isolated from soil samples and the one that had the highest proteolytic
activity, from Susanolu 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.