利用固定化黑曲霉单宁酶制备没食子酸的研究

用海藻酸钙载体包埋单宁酶，制备出转化五倍子单宁成没食子酸能力较好的固定化酶。研究了固定化条件和固定化单宁酶的部分性质，结果表明：最佳固定化条件为海藻酸钠90mg包埋单宁酶546u(3mL,182u/Ml)，在1%～2%CaCl₂中作硬化处理；固定化单宁酶的最适温度为45℃，在10～50℃范围内稳定；其最适Ph值为6.5，在Ph5～7之间基本稳定；在此基础上，进行了没食子酸实验室克量级酶法制备实验，3次实验没食子酸产品的平均产率达到61%。和目前所用工业生产没食子酸的硫酸水解法相当，具有潜在的工业开发价值。

Study on Gallic Acid Preparation by Using Immobilized Tannase from Aspergillus niger

Immobilized tannase which had higher ability of transforming tannin from Chinese gallotannin into GA was prepared by embedding tannase with calcium alginate carrier. The immobilization conditions and some properties of the immobilized tannase were studied. The results showed that: The optimal immobilized parametres were 90 mg sodium alginate, 546 u(182 u/mL) tannase and 1%-2% CaCl2. The optimum temperature and pH value of immobilized tannase were 45 degrees C and 6.5, respectively. It was stable in the temperature range of 10-50 degrees C and between pH5-7. Based on the optimum program, the laboratory gramme-grade preparation experiments of GA were done. The average yield of GA product in three preparations was upto 61%, and was about equivalent to the yield of acidic hydrolytic method which is used to produce GA industrially now. Thus, the research results possessed potential applied value.