Xia Guo-Hua, Liu Wei, Jiang Xiao-Ping, Wang Xiang-Yu, Zhang Ye-Wang, Guo Jianyong
J Nanosci Nanotechnol. 2017 Jan;17(1):370-6. doi: 10.1166/jnn.2017.10964.
Magnetic Fe(3)O(4) nanoparticles were prepared through hydrothermal method and coated with silica on the surface to obtain Fe3O4@SiO2 core–shell nanoparticles. After modification with different functional groups including aldehyde, amine and diimide, the nanoparticles were used as carrier for covalent immobilization of lipase. The nanoparticles with aldehyde groups showed highest immobilization yield (52.8%) and efficiency (86.5%). And the immobilization conditions including pH, temperature and the concentration of enzyme were optimized. After immobilization, the K m of lipase was altered from 2.3 to 3.2 mM. The thermal stability and pH stability were enhanced by immobilization at the investigated conditions: pH 5.0–8.0 and temperature 30–70 °C. After 10 batches conversion of 4-Nitrophenyl palmitate into p-Nitrophenol, the immobilized lipase retained over 75% of the original activity. Compared with the commercial lipase Novozym435, the immobilized lipase showed better stability and higher catalytic efficiency. These results demonstrate that the immobilized lipase on the modified Fe3O4@SiO2 magnetic nanoparticles has enhanced stability and reusability, which make lipase of potential interest in a number of industrial applications.
通过水热法制备磁性Fe(3)O(4)纳米颗粒，并在其表面包覆二氧化硅以获得Fe3O4@SiO2核壳纳米颗粒。在用醛基、氨基和二酰亚胺等不同官能团进行改性后，将这些纳米颗粒用作脂肪酶共价固定化的载体。带有醛基的纳米颗粒表现出最高的固定化产率（52.8%）和效率（86.5%）。并对固定化条件包括pH值、温度和酶浓度进行了优化。固定化后，脂肪酶的K m值从2.3变为3.2 mM。在所研究的条件下（pH 5.0 - 8.0和温度30 - 70°C），固定化提高了热稳定性和pH稳定性。在将棕榈酸对硝基苯酯转化为对硝基苯酚进行10批次反应后，固定化脂肪酶保留了超过75%的原始活性。与商业脂肪酶Novozym435相比，固定化脂肪酶表现出更好的稳定性和更高的催化效率。这些结果表明，固定在改性Fe3O4@SiO2磁性纳米颗粒上的脂肪酶具有增强的稳定性和可重复使用性，这使得脂肪酶在许多工业应用中具有潜在的应用价值。
