该研究探讨单宁酸功能化Fe3O4磁性纳米粒子固定化微泡菌褐藻胶裂解酶的工艺条件。以单宁酸功能化磁性纳米粒子（TA-MNPs）作为固定化酶的载体，通过测定固定化酶的活力和酶活回收率优化微泡菌褐藻胶裂解酶的固定化条件，并利用傅里叶变换红外光谱和透射电镜对固定化酶的结构进行了表征。结果表明，固定载体量为10 mg时，微泡菌褐藻胶裂解酶的最佳固定化条件如下：戊二醛浓度为1.00%，交联时间为2 h，固定化温度为5 ℃，固定化时间为8 h，固定化pH为8.00，加酶量1.20 U，在此条件下固定化酶的活力和酶活回收率达到最大，分别为36.56 U/g和30.55%。傅里叶变换红外光谱分析显示，微泡菌褐藻胶裂解酶成功固定在TA-MNPs表面。透射电镜结果显示，TA-MNPs分散性良好，呈规则球状；固定化酶有明显的聚集现象，粒径变化不大。与游离酶相比，固定化酶的温度稳定性、pH稳定性和存储稳定性提高。微泡菌褐藻胶裂解酶的固定化条件优化研究为该酶的固定化酶制备及应用打下良好的基础。

The immobilization conditions of alginate lyase from Microbulbifer sp. were explored in this study. Tannic acid functionalized magnetic nanoparticles (TA-MNPs) were used as the immobilized carrier to optimize the immobilization conditions of alginate lyase by determining the specific activity and activity recovery of the immobilized enzyme. Then the immobilized enzyme was characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). When the carrier amount was determined to be 10 mg, the optimized immobilization conditions for the alginate lyase were determined as follows: glutaraldehyde concentration 1.00%, cross-linking time 2 h, immobilization temperature 5 ℃, immobilization time 8 h, immobilization pH 8.00, and enzyme dosage 1.20 U. The immobilization effect was the best under these conditions with the specific activity and activity recovery of 36.56 U/g and 30.55%, respectively. The results of FTIR showed that the alginate lyase was successfully immobilized on the surface of TA-MNPs. The results of TEM showed that TA-MNPs had good dispersion and were regular spherical. After immobilization by TA-MNPs, the immobilized enzyme showed the obvious aggregation and little change in particle size. Compared with the free alginate lyase, the immobilized enzyme enhanced thermal stability, pH stability, and storage stability. Optimization of the immobilization conditions of Microbulbifer sp. alginatelyase laid a good foundation for the preparation and application of the immobilized enzyme.

福建省自然科学基金项目（2020J01679）；福建省海洋经济发展补助资金项目（FJHJF-L-2020-1）