脂肪酶在磁性纳米粒子上固定化及其酶学性质研究

Immobilization of lipase on magnetic nanoparticles and its enzymic properties

以Fe_3O_4纳米粒子为载体,碳化二亚胺为交联剂,共价结合制备固定化脂肪酶,探讨脂肪酶固定化影响因素,并对固定化脂肪酶性质进行研究;运用TEM测定其粒径,用FTIR检测脂肪酶—Fe_3O_4磁性纳米粒子耦联。结果表明,脂肪酶固定化适宜条件为:200 mg磁性纳米粒子,加入2 ml 2.5mg/mL脂肪酶磷酸盐缓冲液(0.1mol/L,pH7.5),在4℃超声分散45 min,固定化酶最适pH为7.0,最适温度为45℃,均与游离酶相似;与游离酶相比,该固定化脂肪酶热稳定性明显提高,并具有良好操作和存储稳定性。

Lipase was immobilized on magnetic nanoparticles by using carbodiimide as cross-linking reagent. The immobilization conditions and characterization of the immobilized enzyme were investigated. The size and morphology of magnetic nanoparticles were observed by transmission electron micros （TEM）. The magnetic nanoparticles, free enzyme and binding of lipase onto magnetic nanoparticles were checked using FTIR. The optimal immobilization conditions for lipase were： 2ml of 2.5 mg/mL of lipase in phosphate buffer （0.1 mol/L, pH7.5）reacted with 200mg of magnetic nanoparticles, at 4℃ sonic for 45min. The immobilized enzyme exhibited the maximal activity at pH7.0. The optimal temperatures for immobilized enzyme were 45 ℃, similar to free lipase. Compared with free enzyme, the thermal, operational, and storage stabilities of the enzyme were increased after the immobilization.