亚栖热菌透性化细胞的耦合固定化研究

将海藻酸盐凝胶包埋法与交联法和聚电解质静电自组装覆膜法相耦合，对含有海藻糖合酶活性的亚栖热菌的透性化细胞进行了固定化研究。结果表明，利用重氮树脂和聚苯乙烯磺酸钠对海藻酸凝胶微球交替覆膜，可以显著提高凝胶微球在磷酸盐缓冲液中的稳定性，以碳二亚胺对固定化细胞进行交联处理则可以提高固定化细胞中海藻糖合酶的热稳定性。透性化细胞经包埋－交联－覆膜耦合固定化后，酶活回收率为32％，最适酶反应pH值由6.5左右升至7.0左右，最适反应温度未变，仍为60℃。所得固定化细胞间歇反应时，催化麦芽糖转化为海藻糖的转化率可达60％，重复使用4次（每次50℃、反应24h），酶活损失小于20％，转化率可保持在50％以上。

Co-Immobilization of Permeabilized Meiothermus sp. Cells Containing Trehalose Synthase

Permeabilized cells containing trehalose synthase from Meiothermus sp. CBS-01 was immobilized by the integration of entrapment in alginate beads with cross-linking and electrostatic self-assembly coating technique. Coating on alginate beads with diazo-resin and poly(styrene sulfonate) can protect the beads from degradation in phosphate buffer, whereas cross-linking with carbodiimide improves the thermostability of trehalose synthase entrapped in alginate beads. By co-immobilization of permeabilized cells using entrapment-cross-linking- coating method, the enzyme recovery was 32%, and the optimum temperature of the enzyme was still 60℃, but the optimum pH was shifted from 6.5 to 7. In batch manner, a maximum conversion yield of 60% trehalose from maltose could be reached by the immobilized cells. Within 4 times repeated use of the immobilized cells, and each time was operated at 50℃ for 24h, more than 50% conversion yield of trehalose could be maintained with less than 20% loss of the enzyme activity.