Optimization of azo-keratin hydrolysis by alginate-immobilized Keratinase produced from Bacillus licheniforms

Abstract

Recently, much attention has been paid to Keratinolytic materials which can be converted into feed-stuffs, biofertilizers, glues, and foils or used for production of amino acids. Here, we determined the optimum conditions for keratin hydrolysis by alginate-immobilization of crude keratinase isolated from Bacillus lichenoformis. The results of this study indicated that the optimum pH for keratin degradation by immobilized keratinase enzyme was pH 8. Moreover, the crude enzyme was stable for 2 hours at pH 4, 7 and 10 and retained 55.5%, 60% and 53%, of its activity respectively for immobilized enzyme while free enzyme retained only 40%, 40% and 61%, respectively. The optimum temperature for keratinase activity was 50 oC when immobilized in alginate. At temperatures 30, 45 and 60 oC, keratinase was stable for 2 hours and retained 57%, 66% and 57%, of its activity respectively for immobilized enzyme while free enzyme retained only 51%, 62% and 51%, respectively. Furthermore, the effects of activators and inhibitors on the enzyme activity have been investigated.