Aluminum Oxide Nanoparticles‐Impregnated Aminated Silica Surfaces for Covalent Immobilization of Urease via Glutaraldehyde Activation: Stability and Kinetic Studies

Abstract Jack Bean Urease (Ure, EC. 3.5.1.5) was effectively immobilized on the glutaraldehyde‐activated amino‐functionalized Al 2 O 3 /SiO 2 nanocomposite through covalent conjugations via Schiff base linkages. The chemical composition, size, crystal structure, surface morphology, and particle distribution of the prepared Al 2 O 3 nanoparticles and Al 2 O 3 /SiO 2 nanocomposite were studied by Ultraviolet visible spectroscopy (UV–visible), Fourier‐transform infrared spectroscopy (FTIR), X‐Ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray microanalysis (EDAX), and transmission electron microscopy (TEM) techniques. Immobilized and free urease exhibited the optimum catalytic activity at pH of 8.5, 60 °C, and pH of 7.8, 25 °C, respectively. Kinetic parameters ( K m , V max ) of bound (1.102 mM, 17.73 µM), and free urease (0.998 mM, 23.58 µM) were determined elucidating that the efficiency of urease was enhanced by immobilization. Moreover, immobilized urease preserved more than 50% of initial activity until the 9 th repetitive cycle of utilization and sustained 50% of catalytic activity after 45 days of storage at 4 °C. Thereby, the current outcomes suggest that Al 2 O 3 /SiO 2 ‐APTES‐Glu‐Urease bionanoconjugate would be a viable biocatalyst for enormous proteomic research and biotechnological applications.