Studies on Alkaline Serine Protease Produced by Bacillus clausii GMBE 22

KAZAN D., Bal H., Denizci A. A. , Ozturk N. C. , Ozturk H. U. , Dilgimen A. S. , ...More

PREPARATIVE BIOCHEMISTRY & BIOTECHNOLOGY, vol.39, pp.289-307, 2009 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 39 Issue: 3
  • Publication Date: 2009
  • Doi Number: 10.1080/10826060902953269
  • Page Numbers: pp.289-307


An alkali tolerant Bacillus strain having extracellular serine alkaline protease activity was newly isolated from compost and identified as Bacillus clausii GMBE 22. An alkaline protease (AP22) was 4.66-fold purified in 51.5% yield from Bacillus clausii GMBE 22 by ethanol precipitation and DEAE-cellulose anion exchange chromatography. The purified enzyme was identified as serine protease by LC-ESI-MS analysis. Its complete inhibition by phenylmethanesulfonylfluoride (PMSF) also justified that it is a serine alkaline protease. The molecular weight of the enzyme is 25.4kDa. Optimal temperature and pH values are 60C and 12.0, respectively. The enzyme showed highest specificity to N-Suc-Ala-Ala-Pro-Phe-pNA. The Km and kcat values for hydrolysis of this substrate are 0.347mM and 1141min-1 respectively. The enzyme was affected by surface active agents to varying extents. The enzyme is stable for 2h at 30C and pH 10.5. AP22 is also stable for 5 days over the pH range 9.0-11.0 at room temperature. AP22 has good pH stability compared with the alkaline proteases belonging to other strains of Bacillus clausii reported in the literature.