【Abstract】 Chitosan in 10% acetic acid solution was absorbed on the surface of silica gel particle. Chitosan-silica gel composite carrier was obtained by neutralization of chitosan acetate absorbed on silica gel in 1 mol/L NaOH solution. Lipase was immobilized on this carrier by formaldehyde as cross-linker. The stability of immobilized lipase, such as stability against temperature, acidity and storage in phosphate buffer solution, was examined. In comparison with natural lipase, immobilized lipase showed an improved stability. 70% activity was found for immobilized lipase at 55 ℃, pH 7.5 and 37 ℃, pH 9.5, whereas for natural lipase it was 40%. Moreover, the immobilized lipase kept its activity by 96.6%, 81% and 41% in phosphate buffer solution(pH=7.5) at 37 ℃ in period of 10, 15 and 20 days, respectively, while for natural lipase the activity disappeared under the same condition only in 3 days.更多还原