磁性壳聚糖微球固定化漆酶催化肾上腺素

Preparation of Immobilized Laccase on Magnetic Chitosan Microspheres and Studies of its Characters of Catalyzing Epinephrine

用交联法制备磁性壳聚糖微球,对微球的形貌和结构进行表征和分析,结果表明:微球呈规则的球形,分散比较均匀,粒径在3μm左右。磁性粒子矫顽力为210.6 A/m,接近超顺磁性。以戊二醛为交联剂,将漆酶固定在此磁性壳聚糖微球表面,分别研究了该固定化漆酶和游离漆酶催化肾上腺素的性质。结果表明:固定化漆酶催化肾上腺素的最适温度为55℃,比游离酶升高了10℃,最佳pH值为5.2,游离酶为5.0。在60℃下保温300 min后,固定化酶的催化活性仍保持为原来的75%以上,而在相同条件下游离酶仅保持为原来的10%。固定化酶连续催化肾上腺素10次以后,催化活性仍保持为原来的85%。

Magnetic chitosan microspheres were prepared by glutaradehyde crosslinking technique. The morphology and the size of magnetic chitosan microspheres were measured by SEM. The results showed that magnetic chitosan microspheres were regular sphere with an average size of 3 μm. They had the coercive force of 210.6 A/m and were approximately superparamagnetic. The laccase was immobilized on the magnetic chitosan microspheres. The characteristics of this immobilized laccase in catalyzing epinephrine were studied. The results showed that the optimal catalyzed temperature of the immobilized laccase was 55 ℃, 10 ℃higher than that for the free laccase. The optimal pH for immobilized and free enzyme were 5.2 and 5.0,respectiviely. After the immobilized enzyme was kept at 60 ℃ for 300 min, it still had 75 % of initial enzyme activity, while the activity of free enzyme could only remain 10 % under the same conditions. After 10 cycles of operation, the activity of immobilized enzyme remained over 85 % of its initial activity.