环糊精葡萄糖基转移酶在壳聚糖上的固定化

Immobilization of Cyclodextrin Glucanotransferase on Chitosan

以甲醛作为活化剂将环糊精葡萄糖基移酶（ＣＧＴａｓｅ，ＥＣ，３．２，２．１９）固定在壳聚糖上。发现ＣＧＴａｓｅ经固定化后，最适温度没有改变，最适ｐＨ从６．０移到５．０，热稳定性及ｐＨ稳定性都有所提高，在ｐＨ８．５和５０℃下，经过４次分批反应，固定化酶保留约６６％活力，柱式连续反应的半衰期大约为６天。

Cyclodextrin glucanotransferase(CGTase EC,3.2.1. 19 ) of Alcalibacterium cyclodex-trinogenes sp.nov,was immobilized on chitosan pretreated with formaldehyde. Various properties ofimmobilized CGTase such as the pH-activity curve,the temperature-activity curve, PH and thermalstability batch reusability and column reaction stability were studied.As a result of immobilization,thepH optimum shifted from pH 6.0 to pH 5. 0 whereas the temperature optimum did not change. The pHand thermal stability of immobilized CGTase were superior to that of soluble enzyme. The immobilizedCGTase retained about 66% of its original activity after 4 times of repeated use by the batch system at50℃ and pH 8.5,the half life under the same conditions by the column method was about 6 days.