Extruction of keratinase from the local isolate Bacillus licheniformis and partially purified and characterized

Abstract

The keratinase produced from local isolate Bacillus licheniformis was purified by two steps included precipitation by ammonium sulphate with 40% saturation; followed by ion exchange using CM-Cellulose column. The enzyme was purified to 12.6 times in the last step with an enzyme yield of 17%. Enzyme characterization results indicated that: The optimal pH for enzyme activity was 7.5 and it was stable at 7-9.5. The optimal temperature for enzyme activity was 50°C and it was stable for 30 min at 25-45 °C. Substrate specifity was tested using casein, Bovine serum albumin, gelatin, hooves, human hair, chicken feathers and wool; higher specifity was recorded using casein gave 0.6 unit /ml. The enzyme was inhibited by PMSF and metal ions like Hg+2, Fe+2, Cu+2 and Mn+2, and activated by Ca+2, Mg+2, Zn+2and Al+3.