Characterization and immobilization of liposome-bound cellulase for hydrolysis of insoluble cellulose.

The liposome-bound cellulase was prepared by covalently coupling cellulase with the enzyme-free liposomes bearing aldehyde groups so that cellulase was located solely on the outer membrane of liposomes. The modified cellulase possessed the higher activity efficiency and lipid-based specific activity than the cellulase-containing liposomes reported previously. The enzyme-free liposomes bearing aldehyde groups were covalently immobilized with the chitosan gel beads and the free cellulase was coupled with the treated gel beads to prepare the immobilized liposome-bound cellulase. The activity efficiency of the immobilized liposome-bound cellulase was much higher than that of the conventionally immobilized cellulase. The results on reusability of the immobilized liposome-bound cellulase in the hydrolysis of either soluble or insoluble cellulose showed that the immobilized liposome-bound cellulase had the higher remaining cellulase activity and reusability than the conventionally immobilized cellulase for the hydrolysis of either type of cellulose. The liposomal membrane was suggested to be efficient in maintaining the cellulase activity during the hydrolysis.