The Research Of Trypsin Immobilization Technology And It's Application In Aquatic Product Processing

Chitin and Chitosan as functional materials have a unique set of characteristics.Immobilized enzyme with chitosan as carrier have been widely used in wine industry,sugar industry,fisheries, and for wastewater treatment,the fixed point pollution control and so on.In this paper,immobilized trypsin was prepared using porous chitosan beads as carrier and glutaraldehyde as crosslinking agent.The conditions of preparation porous chitosan beads,the effects of the concentration of both enzyme and reagent,the pH value of the solution,the temperature,and the reaction time on the activity in the whole immobilize process were studied.We also researched the character of immobilized trypsin,the condition of hydrolysis silver carp,the degree of hydrolysis,the soluble protein yield and the nitrogen dissolved index.According to trial,the optimum condition of prepare porous chitosan beads are as following: concentration of chitosan was 3%,cross linking solution was 4%NaOH:95%ethanol,glomerating time was 3h;the optimum immobilize condition was pH 7.0,concentration of glutaraldehyde 0.5%,concentration of trypsin 7mg/mL,temperature 15℃,and reaction time 24h.At this condition the activity of immobilized trypsin was 472.39u/g wet particles,immobilized efficiency was 42.9%.The results indicated that the immobilized trypsin displayed the optimum activity at pH7.0～9.0,temperature 30℃～60℃and Km values 9.89mg/mL.And free trypsin showed the optimum activity at pH 7.0～7.5,temperature 50℃and Km value 8.99mg/mL. Compared with free trypsin,the immobilized trypsin had better stability in thermal and pH storage.Silver carp protein was hydrolyzed by immobilized trypsin which was reused 4 times, the activity of the immobilized trypsin remained 46.06%.Optimum temperature was 40℃,the degree of hydrolysis was 8.73%,the soluble protein yield was 69.55%and the nitrogen dissolved index was 62.24%.