Abstract:Making chitosan as raw material, chitosan microspheres were prepared. The morphology and structure of the microspheres were characterized by SEM. Composite enzyme was immobilized by using chitosan microspheres as carrier. The influence of factors affecting the effect of immobilization enzyme was investigated via single factor test and orthogonal test. The enzymatic properties of immobilized enzyme were investigated also. The application effect of using the immobilized enzyme to hydrolysis geniposide to genipin was researched via HPLC method.The results indicated that, the average diameter of chitosan microsphere was about 2 mm and has a porous surface. The optimal conditions for enzyme immobilization were: adsorption time 4 h, crosslink time 1 h, concentration of crosslinking agent 0.2%. The optimum applying temperature for immobilized enzyme was 60 ℃, and 55 ℃ for free enzyme. Both temperature stability and pH stability of immobilized enzyme were higher than that of free enzyme. Both of the optimum pH for immobilized enzyme and free enzyme was 5.0. The residual enzyme activity of immobilized enzyme was more than 50% after being used for 8 times. For immobilized enzyme, wet storage was suitable for short-term application and storage, however, dry storage was suitable for long-term storage.The effect was perfect using the immobilized enzyme to hydrolysis geniposide to genipin.
