单分散磁性纳米粒子固定化猪胰脂肪酶的研究

借助溶热法制备了一种亲水及生物相容良好的Fe3O4磁性纳米粒子,用γ-氨丙基三乙氧基硅烷直接对所得磁性粒子表面改性,然后用戊二醛偶联法制得了固定化猪胰脂肪酶.表征研究显示,所得磁性粒子粒径约200 nm,具有良好的单分散性和磁响应性.考察了戊二醛浓度、给酶量和反应时间对脂肪酶固定化过程的影响,并通过游离酶与固定化酶的比...

STUDY ON LIPASE IMMOBILIZATION ON MONODISPERSE MAGNETIC NANOPARTICLES

A simple,effective,green and economic approach of lipase immobilization is provided in this article.Single-crystal,hydrophilic,biocompatible Fe3O4magnetic nanoparticles as good carriers were prepared via a solvothermal reduction method.Microsphere diameters were observed to be about 200 nm by transmission electron microscopy(TEM).Superior monodispersity was demonstrated,and saturation magnetization was found to be 83.7 emug-1.The resulting products were modified directly with γ-aminopropyltriethoxysilane(APTS).Porcine pancreas lipase(PPL) was covalently immobilized on the obtained particles using glutaraldehyde as a coupling reagent.The enzymatic activities of free and immobilized PPL were measured by titration of fatty acid which came from the hydrolysis of olive oil and the amount of protein was determined by the Bradford method using bovine serum albumin(BSA) as a standard.The factors related with the activity of the immobilized lipase on prior carriers,such as the pH value of the immobilized reaction,the concentration of glutaraldehyde and the amount of enzyme were investigated.The immobilized lipase exhibited excellent thermal stability and reusability in comparison with free enzyme.High activity recovery(54.8%) of the immobilized lipase was achieved and the amount of protein was up to 120 mg/g.This immobilized lipase can be reused 10 times with the enzymatic activity remained above 90%.