Hydroxyapatite-decorated ZrO2 for α-amylase immobilization: Toward the enhancement of enzyme stability and reusability

Herein, the immobilization of alpha-amylase onto hydroxyapatite (HA) and hydroxyapatite-decorated ZrO2 (10%wt) (HA-ZrO2) nanocomposite were investigated. The immobilization yield was 69.7% and 84% respectively. The structural differences were characterized using X-Ray diffraction, attenuated total reflectance-Fourier transform infrared spectra, Raman, and scanning electron microscope. After 10 repeated cycles, the residual activity of immobilized alpha-amylase onto HA and HA-ZrO2 nanocomposite was 46% and 70%, respectively. The storage stability was recorded to be 27%, 50% and 69% from its initial activity in the case of free and immobilized enzyme onto HA and HA-ZrO2 nanocomposite, respectively after 8 weeks. The pH-activity profile and temperature revealed pH 6.0 and temperature 50 degrees C as the optimal values of free alpha-amylase, while the optimum values for alpha-amylase on HA and HA-ZrO2 was shifted to pH 6.5 and 60 degrees C after immobilization. The immobilized alpha-amylase onto HA-ZrO2 showed comparatively higher catalytic activity than the free alpha-amylase. The Km value after the immobilization process onto HA was 2.1 folds highly than that of the free enzyme. In conclusion, it can be inferred that HA-ZrO2 is more sustainable and beneficial support for enzyme immobilization and it represents promising supports for different uses of alpha-amylase in the biomedical applications. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the immobilization of alpha-amylase on hydroxyapatite (HA) and hydroxyapatite-decorated ZrO2 (HA-ZrO2) nanocomposite, finding that the enzyme immobilized on HA-ZrO2 showed higher catalytic activity and improved storage stability. The results suggest that HA-ZrO2 is a more sustainable and beneficial support for enzyme immobilization, with promising applications in the biomedical field.