( )Immobilization of alpha-amylase enzyme on a protein @metal-organic framework nanocomposite: A new strategy to develop the reusability and stability of the enzyme

Abstract

Metal-organic structures (MOFs) have been designed for a wide range of applications due to their high porosity, large surface area, and flexibility. For the first time in this work, the successful immobilization of alpha-amylase is confirmed by the use of ZIF-8 as easy and good support. The morphology, functional groups, and chemical composition of the support and immobilized a-amylase were tested using different methods such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA). The enzymatic activities of the immobilized olibanum-bovine serum albumin@zeolitic imidazolate frameworks nanocomposite (OLB/BSA@ZIF-8)-alpha-amylase were compared with the free one. The pH and thermal stability of the OLB/BSA@ZIF-8-alpha-amylase were significantly enhanced compared to the free enzyme. The OLB/ BSA@ZIF-8-alpha-amylase displayed excellent long-term storage stability, which could protect more than 90% of the initial activity for 8 weeks. Besides, the OLB/BSA@ZIF-8-alpha-amylase had high reusability, which showed a high degree of activity (more than 81%) after 20 cycles. This is the first study that uses OLB/BSA@ZIF-8 nanocomposite as immobilizing support for the immobilization of alpha-amylase. Improved catalytic efficiency (V-max/K-m) values, reusability, and storage stability of immobilized a-amylase can make it suitable in industrial and biotechnological applications.