建立环境友好型的酶法制备高脱乙酰度壳聚糖的最佳工艺。以淡水小龙虾壳为原料,经EDTA法提取甲壳素,采用超声辅助CDA酶法制备壳聚糖;在预实验基础上,利用响应面法优化超声辅助CDA酶法制备壳聚糖工艺。结果表明:酶法制备高脱乙酰度壳聚糖的最佳条件为超声时间60 min,超声功率476 W,加酶量9.45%,酶解温度50℃,酶解时间3.5 h,在此条件下制备的壳聚糖脱乙酰度高达91.09%,黏度为95 m Pa·s,相对得率81.87%。该制备方法与单一超声法及传统碱法相比具有无任何环境污染、产品脱乙酰度高、产品性质稳定等优势。

Optimum environment-friendly enzyme method for preparation of chitosan with high degree of deacetylation was established. Using freshwater crayfish shell as raw material,the chitosan was prepared by ultrasonic assisted CDA enzyme method after extraction of chitin by EDTA method. Then chitosan preparation technology combined with ultrasonic-assisted CDA enzymatic response was optimized by response surface method based on preliminary experiment. The results showed that the optimum enzymatic preparation condition for chitosan with high degree of deacetylation was as follows: the ultrasonic time 60 min,ultrasonic power 476 w,enzyme dosage 9. 45%,temperature50 ℃,hydrolysis time 3. 5h. Under this condition,the degree of deacetylation of chitosan was as high as 91. 31%,viscosity was 95 m Pa·s,and relative yield was 81. 87%. Compared with the ultrasonic method alone and the traditional alkali method,the above preparing process had remarkable advantages such as without environmental pollution,high degree of deacetylation,stability and so on,which would not only lay the foundation for the environmentally friendly industrialization production of chitosan,but also conform to the economic development trend in future.