包埋-交联法固定大肠杆菌细胞制备γ-氨基丁酸的研究

Preparation of γ-aminobutyric acid by immobilized Escherichia coli cells with the embed-cross linked method

以明胶为载体,戊二醛为交联剂,采用包埋-交联复合固载法固定大肠杆菌细胞,研究明胶浓度、菌体加入量和戊二醛对固定化大肠杆菌细胞谷氨酸脱羧酶活力的影响,并将固定化大肠杆菌细胞用于制备γ-氨基丁酸。结果表明:0.1g大肠杆菌菌粉分散在30mL、13%的明胶溶液中,转变成凝胶后再用0.5%戊二醛溶液20mL交联2h,固定化细胞的谷氨酸脱羧酶活力最高;采用15g固定化细胞在pH值为4.0、温度40℃转化20.0mL、60mmol/L的L-谷氨酸底物,反应11h的转化率达95%,重复进行6次转化反应,转化率达95%的时间是20h。该包埋-交联法固定化大肠杆菌细胞在制备γ-氨基丁酸上有较好的工业化应用前景。

Escherichia coil cells were immobilized with the embed-cross linked method using gelatin as carrier and glutaraldehyde as cross-linked reagent. The effects of gelatin concentration, glutaraldehyde concentration and bacterium mass on the activity of glutamate decarboxylase in immobi- lized E. coli cells were investigated. The γ-aminobutyric acid prepared by the immobilized cells was studied. The results showed that the optimal im- mobilized conditions was 0. 1 g E. coli celt powder dispersing in 30ml, 13% gelatin solution to form gel, then cross linking 2h with 0.5% glutaralde- hyde with the biggest activity of glutamate decarboxylase. The conversion yield can be up to 95% when using 15g immobilized cell under pH value 4.0, and 20.0ml（60mmol/L） L-glutamic acid as substrate at 40℃ for the reaction time 1 lh. For same yield, the reaction time would be 20h when im- mobilized cells were recycled 6 times. This embed-cross linked method has potential for the preparation of γ-aminobutyric acid in the industry.