Purification and biochemical characterization of Arabian balsam α-amylase and enhancing the retention and reusability via encapsulation onto calcium alginate/Fe2O3 nanocomposite beads

In this study, Arabian balsam alpha-amylase was purified using the three-step purification method with 9.8-fold pu-rification and 7% recovery. The purified alpha-amylase's molecular weight was 85 kDa. Calcium alginate incorporated with iron (III) oxide nanoparticles was applied as an immobilizing support for alpha-amylase. The immobilized alpha-amylase was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. In addition, the optimum conditions for immobilization efficiency, immobilization time, reusability, kinetic parameters, and the effect of pH for the immobilization process were examined. After storage, about 87% of the initial activity was maintained at 4 degrees C for 60 days. The immobilized enzyme exhibited enhanced stability compared to the soluble enzyme in relation to pH and temperature. The immobilized enzyme provided the following kinetic variables: 0.455 mg/mL, 4050 s(-1), 28.57 mu mol maltose/mL, and 8900 s(-1) mg(-1) mL for Km, kcat, Vmax, and kcat/Km, respectively, compared with 1.798 mg/mL, 5980 s(-1), 42.19 mu mol maltose/mL, and 3326 s(-1) mg(-1) mL for the soluble enzyme. The total phenolic contents of the soluble and immobilized alpha-amylase-treated wheat kernels were increased by 1.26 and 1.31 fold, respectively. Purified alpha-amylase from Arabian balsam can thus be successfully used to enhance the antioxidant capacity of cereals. (C) 2020 Elsevier B.V. All rights reserved.