Abstract:Papain was immobilized on sodium alginate-chitosan and nylon, respectively. The immobilization conditions and characterization of the immobilized enzyme were studide. When 1 mg g-1 carrier papain (PA) was loaded on sodium alginate-chitosan (IPSAC), the IPSAC activity was 39.2 U, and the recovery of activity was 21.1%. As PA was loaded 1 mg on one block nylon (3 cm×3 cm), the IPN activity was 35.6 U, and the recovery of activity was 19.2%. The optimum pH of PA, IPSAC and IPN were 7.2, 7.2 and 6.8, respectively. PA and IPSAC were stable when the temperature was lower than 70℃, while IPN was stable below 50℃. The half-life of IPSAC and IPN were 59 d and 66 d, respectively.