Department of Environmental Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Department of Biological Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Appl Biochem Biotechnol. 2022 Aug;194(8):3527-3540. doi: 10.1007/s12010-022-03890-z. Epub 2022 Apr 7.
In this study, nitrilase (Nit) was immobilized in zeolite imidazole framework-90 (ZIF-90) by one-pot biomimetic mineralization strategy. The structure, morphology and functional groups of ZIF-90 and immobilized enzyme Nit@ZIF-90 were characterized by scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). Circular dichroism (CD) proved that the immobilized method of encapsulation in ZIF-90 could effectively maintain the intrinsic conformation of Nit. Meanwhile, the stability and reusability of Nit@ZIF-90 were systematically evaluated. Compared with the free enzyme, the thermal, pH and organic solvents stability of Nit@ZIF-90 were significantly increased. Further, Nit@ZIF-90 exhibited better reusability during the hydrolysis of acrylonitrile and retained 48.34% of the initial activity after 10 cycles. Besides, the Ni@ZIF-90 had preferable storage stability, which showed a high degree of residual activity (more than 64 %) after storage at 4 °C for 7 d. The improved stability and reusability of the Nit@ZIF-90 implied that it could be used as a potential effective biocatalyst for hydrolysis of nitrile compounds in industrial application.
在这项研究中，采用一锅仿生矿化策略将腈酶（Nit）固定在沸石咪唑骨架-90（ZIF-90）中。通过扫描电子显微镜（SEM）/能谱（EDX）、透射电子显微镜（TEM）、X 射线衍射（XRD）、热重分析（TGA）和傅里叶变换红外光谱（FT-IR）对 ZIF-90 和固定化酶 Nit@ZIF-90 的结构、形貌和官能团进行了表征。圆二色性（CD）证明了 ZIF-90 中的包埋固定化方法可以有效地保持 Nit 的固有构象。同时，系统评价了 Nit@ZIF-90 的稳定性和可重复使用性。与游离酶相比，Nit@ZIF-90 的热稳定性、pH 稳定性和有机溶剂稳定性显著提高。此外，在丙烯腈水解过程中，Nit@ZIF-90 表现出更好的可重复使用性，经过 10 次循环后仍保留初始活性的 48.34%。此外，Ni@ZIF-90 具有较好的储存稳定性，在 4°C 下储存 7 天后，仍保持较高的剩余活性（超过 64%）。Nit@ZIF-90 稳定性和可重复使用性的提高表明，它可以作为一种潜在的有效生物催化剂，用于工业应用中腈类化合物的水解。
