Abstract: Using glutaraldehyde as the crosslinker, chymotrypsin was immobilized onto chitosan–arginine resin which was porous and grafted with a flexible and hydrophilic spacer. The optimal conditions of immobilization were as following: ratio of enzyme loading/ wet resin (mg/g) was 20:1, crosslinker dose was 10 mL 1.0% glutaraldehyde solution/ 1.5 g wet resin, immobilizing time was 60 min, while the relative activity was 68.95%. The enzymatic properties of immobilized chymotrypsin were as following: its enzymatic reaction reached the maximum rate in 10 min, with a similar catalysis time curve to soluble enzyme; its Km value was 8.36 mg/mL, 1.52 times higher than that of soluble enzyme; its optimal temperature was 70 ℃, 10 ℃ higher than that of soluble enzyme; its optimal pH was 5.92 which deviated 2 units to acid side compared with soluble enzyme. Moreover, the immobilized chymotrypsin had high thermal stability and storage stability, with the half-life of 8h at 75 ℃ and 46 days at 4 ℃.

Key words: chitosan, L-arginine, chymotrypsin, cross-linking, immobilization