Abstract: Tannase was immobilized on chitosan sponge using glutaraldehyde as cross-linking reagent. The immobilization conditions were optimized as following: 6 mg tannase immobilized on 1 g chitosan sponge under pH 5.0 and 4 ℃ for 8 hours. On the optimal conditions the enzyme activities and stability are both the highest. The Km value of the immobilized tannase is 3.83 mmol/L, while that of the free tannase is 33 mmol/L. As far as the stabilities to pH and heat changing are concerned, the immobilized tannase is also superior to free tannase, and the stable pH range is wider, especially on the low side.

Key words: tannase, chitosan, immobilization