Encapsulation of HRP Enzyme onto a Magnetic Fe3O4 Np–PMMA Film via Casting with Sustainable Biocatalytic Activity

Wesam H Abdulaal,Reda M El-Shishtawy,Yaaser Q Almulaiky

doi:10.3390/catal10020181

Abstract

Horseradish peroxidase (HRP) enzyme was effectively encapsulated onto an Fe3O4 nanoparticle–polymethyl methacrylate (PMMA) film via the casting method. The HRP was immobilized on the 0.5% Fe3O4Np–PMMA film and characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Moreover, the reusability, thermal stability, optimum pH, optimum temperature, the influence of metal ions, and the effects of detergent and organic solvent were investigated. After optimizing the immobilization conditions, the highest efficiency of the immobilized enzyme was 88.4% using 0.5% Fe3O4Np–PMMA. The reusability of the immobilized HRP activity was 78.5% of its initial activity after being repeatedly used for 10 cycles. When comparing the free and immobilized forms of the HRP enzyme, changes in the optimum temperature and optimum pH from 30 to 40 °C and 7.0 to 7.5, respectively, were observed. The Km and Vmax for the immobilized HRP were estimated to be 41 mM, 0.89 U/mL for guaiacol and 5.84 mM, 0.66 U/mL for H2O2, respectively. The high stability of the immobilized HRP enzyme was obtained using metal ions, a high urea concentration, isopropanol, and Triton X-100. In conclusion, the applicability of immobilized HRP involves the removal of phenol in the presence of hydrogen peroxide, therefore, it could be a potential catalyst for the removal of wastewater aromatic pollutants.

Highlights

Enzymes are macromolecules that catalyze the most complex chemical reactions under particular and defined conditions
This study aims to invent a new, cost-effective method for HRP enzyme immobilization by encapsulating horseradish peroxidase (HRP) on an iron magnetic nanoparticle–polymethyl methacrylate (Fe3 O4 Np–PMMA) film using the casting method to describe the physical characterization and biochemical properties of free and immobilized HRP in order to improve its optimal conditions and retain its activity
Magnetic nanomaterials were used in protein immobilization in various capacities [16,19]; for example, non-modified magnetic Fe3 O4 nanoparticles were physically immobilized on peroxidase, preserving 55% of original activity after being used 10 times [20]

Summary

Introduction

Enzymes are macromolecules that catalyze the most complex chemical reactions under particular and defined conditions. Enzymes have limitations regarding their non-biological applications such as their industrial applications. Enzymes for some industrial processes must be immobilized. A technique which has different roles in soluble enzymes. The immobilization of an enzyme is an important technique to minimize the inhibition caused by reaction materials, reaction products, solvents, inhibitors, or any environmental conditions that affect the soluble enzyme. Enzyme immobilization techniques result in excellent enzyme properties such as high functional and uptake stability, high selectivity, enhanced sensitivity, better short-term response, and extraordinary reproducibility [1,2]

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