固定化细胞生产L-苯丙氨酸研究

STUDIES ON PRODUCTION OF L -PHENYLALANINE BY IMMOBILIZED CELLS

用聚乙烯醇（ＰＶＡ）凝胶包埋固定假单胞菌Ｅ４－１０６细胞，最佳ρ（ＰＶＡ）为８０ｇ／Ｌ；最适湿细胞包埋量为每ｍｌ凝胶０．３ｇ；转氨酶活力回收率为７８％，连续反应２１批次后，固定化细胞酶活力为初始最高活力的９１％；用固定化细胞进行间歇式批次反应，结果表明其酶活性半寿期为４个月；制得的固定化细胞为直径约３ｍｍ的珠状颗粒，机械强度良好，间歇式批次反应１０个月。

The whole cells of Pseudomonas sp. E4-106 containing high transaminase activity were immobilized in polyvinyl alcohol (PVA) gel. The optimal concentration of PVA was 80 g/L and the optimal cell loading by direct entrapment was 0.3 g of wet weight cells per mL gel. Recovery rate of the enzyme activity of the immobilized cells was 78%. After 21 batches of reaction, the enzyme activity decreased to 91% of the initial. Discontinuous batch reaction by using the immobilized cells indicated that the half-life of the enzyme activity was about 4 months. The beads, 3 mm in diameter, prepared by adding homogeneous mixture of the cells and PVA to a solution containing 25 g/L sodium tetraborate decahydrate and 50 g/L sodium chloride as droplets, were so strong mechanically that no disruption of the gel beads was observed in 10 months.