固定化大肠杆菌细胞生产γ-氨基丁酸的研究

STUDIES ON PRODUCTION OF γ-AMINOBUTYRIC ACID BY IMMOBILIZED ESCHERICHIA COLI CELLS

用海藻酸钙包埋法将大肠杆菌细胞制成固定化细胞,与1%谷氨酸溶液进行间歇反应、连续搅拌式反应及连续柱式反应生产γ-氨基丁酸。谷氨酸溶液用0.2mol/L醋酸-醋酸钠缓冲液调至pH4.4,温度37℃。间歇反应在微生物多用培养箱旋转摇床上120r/min振荡反应,每批反应6h,100%的谷氨酸可转化为γ-氨基丁酸。连续搅拌式反应在三角瓶反应器中进行,以6ml/h的流速输入底物溶液,输出反应液,转化率达85%。连续柱式反应在上部膨大、顶端开口的特殊柱反应器中进行,控制流速12ml/h,95%以上的谷氨酸可被转化成γ-氨基丁酸。

Whole cells of E. coli were immobilized by entrapping in a calcium alginate gel lattice followed by cross-linking with glutaric dialdehyde. Conditions for the production of γ-aminobutyric acid (GABA) were investigated comparing three methods: batch process, stir-continous, and column-continous.The optimal pH and temperature for the production of GABA was 4.4 and 37℃, respectively. The batch process was operated on a rocker at 120r/min; stir-contious reaction in a flask reactor at, 6ml/h; column-continous production in special column reactor at 12ml/h. About 85%—100% of L-glutamate was converted to GABA under suitable conditions. It was found that the column-continous production has an advantage over others.