Production and charactrization of keratinase enzyme from natural isolate bacillus strains

Bacillus sp are microorganism's species which can produce keratinase enzyme. The enzyme has ability to degrade keratine substrate and it belongs to extraceluler inducible enzyme group. In this study, proteolitic activities of Bacillus strains isolated from soil contaminated with poultry farm waste were determined on Skim Mmilk Agar. 63 Bacillus strains were identified as proteolytic. Nine of these strains showed activity with the keratin-azure substrate and were determined to be keratinolytic. Among the isolated strains, strain no: 30 was selected as the best keratinase producer. The basal feather medium was used to produce keratinase. The optimum production conditions of the enzyme were determined as pH=8.0 and 30ºC. The optimum activity of the enzyme was determined at pH: 9.0 and 50 ºC. When the enzyme was pre-incubated for 30 minutes at 50-100 ºC, it preserved its activity at a high rate (90%) after pre-incubation at 50 ºC and showed no activity after pre- incubations above 70 degrees. After 30 minutes of pre-incubation of the enzyme with 1-5 mM concentrations of chemical and metal ions, it was determined that tween 20 (215%) and SDS (204%) significantly increased the activity, and EDTA (76%), Urea (40%), ZnCl2 (28%), MgCl2 (51%), NiCl2 (24%), CaCl2 (56%), HgCl2 (0), CuCl2 (83%) decreased the activity. Keywords: Bacillus sp., Keratin, Keratinase, Enzyme production, Characterization