Using chitosan as a source, the chitosan microspheres were prepared by suspension crosslinking technique. Their properties were determined and analysed. The results indicated that they complexed functions of chitosan with those of macromolecule microspheres. Then as the carrier, the chitosan microspheres were used to immobilize papain by absorption crosslinking method. The optimum conditions for immobilization were studied. The results were as follows: the optimum load of enzyme was 1.92 mg enzyme/g carrier, the absorbing time was 12 h and the temperature 4～8 ℃; then interacted for 3 h at 4～8 ℃ with 0.5% glutaraldehyde. The activity and the activity recovery of the immobilized papain were 38.49 U/g carrier and 66.60% respectively. Key words:chitosan microspheres; papain;
