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

• Main Authors: Wesam H. Abdulaal, Yaaser Q. Almulaiky, Reda M. El-Shishtawy
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Catalysts
• Subjects: casting method; encapsulation; hrp; magnetic fe₃o₄ np; characterization; pmma
• Online Access: https://www.mdpi.com/2073-4344/10/2/181

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.