功能化磁性纳米颗粒固定化脂肪酶研究

用葡萄糖酸对Fe3O4磁性纳米颗粒表面进行修饰，然后用水溶性碳化二亚胺（EDC）作偶联剂，对脂肪酶进行固定化。考察了偶联剂浓度、给酶量和反应时间对脂肪酶固定化过程的影响。结果表明，制备功能化磁性颗粒固定化酶的最佳条件为：偶联剂浓度为12．5mg／mL磷酸缓冲液（PBS），给酶量为2．5mg／mLPBS，反应时间为24h。固定化脂肪酶表现出优异的热稳定性，60℃时酶活为游离酶的6倍。重复使用10次后，酶促活力依然保持80％以上。

Study on lipase immobilization on functional magnetite nanoparticles

Fe3O4 Magnetic nanoparticles as carriers were coated by gluconic acid. Lipase was covalently immobilized on the particles using water-soluble carbodiimide （EDC） as a coupling reagent. The factors re- lated with the activity of the immobilized lipase on carriers, such as the concentration of EDC, the amount of enzyme, and the time of the immobilized reaction were investigated. The result showed that the best con- centration of coupling reagent was 12.5 mg/mL PBS ;the amount of enzyme was 2.5 mg/mL PBS, and the reaction time was 24 h. The immobilized lipase had better resistance to temperature in comparison to the free form. This immobilized lipase can be reused 10 times with the enzyme activity remained above 80%.