Zhao J L
Biomedical Engineering Institute, Xi'an Jiaotong University.
Chin J Biotechnol. 1989;5(2):105-11.
E. coli cells with glutamate decarboxylase activity were immobilized by entrapment in calcium alginate gel lattices, followed by cross-linking with glutaric dialdehyde to increase mechanical strength. A large number of cells was immobilized in the gel, resulting in high enzyme activity. Optimum conditions for gamma-aminobutyric acid production were investigated. A comparative study of three reactor modes, i.e., batch, continuously stirred, and continuous column, found the optimal pH and temperature for -aminobutyric acid production to be 4.4 and 37 degrees C respectively. The batch process was run on a shaker at 120 r/min, the continuously stirred reaction (in a flask reactor) at 6 ml/h, and column production (in a special column reactor) at 12 ml/h. Conversion of the L-glutamate to gamma-aminobutyric acid was about 85-100% under these conditions. The immobilized cells could be regenerated by incubation in phosphopyridoxal coenzyme solution when enzyme activity and immobilized-cell throughput declined. The column-type process had some advantages over the others.
将具有谷氨酸脱羧酶活性的大肠杆菌细胞通过包埋在海藻酸钙凝胶晶格中进行固定，然后用戊二醛交联以提高机械强度。大量细胞被固定在凝胶中，从而产生了高酶活性。研究了γ-氨基丁酸生产的最佳条件。对三种反应器模式（即分批、连续搅拌和连续柱式）进行的比较研究发现，γ-氨基丁酸生产的最佳pH值和温度分别为4.4和37℃。分批过程在摇床上以120转/分钟运行，连续搅拌反应（在烧瓶反应器中）以6毫升/小时运行，柱式生产（在特殊柱式反应器中）以12毫升/小时运行。在这些条件下，L-谷氨酸向γ-氨基丁酸的转化率约为85%-100%。当酶活性和固定化细胞通量下降时，固定化细胞可通过在磷酸吡哆醛辅酶溶液中孵育来再生。柱式过程比其他过程具有一些优势。
