磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷的研究

Study on Hydrolysis of Naringin by Immobilized Naringinase on Magnetic Silica Chitosan Microspheres

摘要:

本文在磁性Fe3O4外包覆一层SiO2，再在其外包裹壳聚糖制备出磁性硅基壳聚糖微球（MSC），对MSC进行环氧基修饰后用于柚苷酶的固定化研究，并对磁性硅基壳聚糖微球固定化柚苷酶水解柚皮苷的pH、温度、操作和储藏稳定性进行了考察。通过单因素实验，确定了环氧基修饰的磁性硅基壳聚糖微球（MSCE）固定化柚苷酶的最佳工艺条件为：pH 3.0，温度30 ℃，时间4 h、给酶量57.48 U/mL。在此条件下，MSCE固定化柚苷酶的载酶率、酶活回收率和酶比活力分别为31.29%、88.92%和409.33 U/g。与游离柚苷酶相比，MSCE固定化柚苷酶用于水解柚皮苷具有良好的pH稳定性和温度稳定性，重复使用8次后仍具有53.36%的相对酶活力，4 ℃条件储存一个月后仍具有80.97%的相对酶活力。

Abstract:

Magnetic silica chitosan microspheres (MSC) were prepared by orderly grafting SiO2 and chitosan layer on the surface of Fe3O4 nanoparticles, and after modified with epoxy groups, the microspheres were used for immobilization of naringinase. The pH, temperature, storage and operational stability of naringin hydrolysis by the immobilized naringinase were investigated. The optimal immobilization conditions were determined as follows: immobilization pH, temperature and time were 3.0, 30 ℃ and 4 h, respectively, and 57.48 U/mL of crude naringinase broth activity. As a result, the binding efficiency, activity recovery rate and specific activity of the immobilized naringinase were 31.29%, 88.92% and 409.33 U/g, respectively. Comparing with free naringinase, the immobilized naringinase used for naringin hydrolysis showed better pH stability and thermal stability, and it retained 53.36% residual activity after 8 consecutive operations and 80.97% residual activity after one month of storage.