Immobilization of papain and its application to silk peptide production

The degummed fibroin was treated with w=0.5% glutaraldehyde at normal temperature for 40 min and got the activated fibroin. Using the activated fibroin as carrier, the papain was immobilized by covalence-crosslinking method. The result showed that the optimum conditions for immobilization were: the enzyme loading amount was 0.36 mg/g silk fibroin; the temperature was 4 ℃ ; the immobilizing time was 6 h; and the pH value was 7.5. The activity and activity recovery of the immobilized papain were 1 786.93 U/g and 69.54% , respectively.