Immobilization of Horseradish Peroxidase on Multi-Armed Magnetic Graphene Oxide Composite: Improvement of Loading Amount and Catalytic Activity.

Junhui Rong,Zijuan Zhou,Wenli Zhang,Yun Wang,Liang Ni,Juan Han,Chunmei Li

doi:10.17113/ftb.57.02.19.5832

Junhui Rong, Zijuan Zhou + Show 5 more

Open Access

https://doi.org/10.17113/ftb.57.02.19.5832

Copy DOI

Abstract

SUMMARYIn this study, a novel type of multi-armed polymer (poyltehylene glycol, PEG) magnetic graphene oxide (GO) composite (GO@Fe3O4@6arm-PEG-NH2) has been synthesized as a support for immobilization of horseradish peroxidase (HRP) for the first time. The loading amount of HRP was relatively high (186.34 mg/g) due to the surface of carrier material containing a large amount of amino groups from 6arm-PEG-NH2, but degradation rate of phenols was also much higher (95.4%), which is attributed to the synergistic effect between the free HRP (45.4%) and the support material of GO@Fe3O4@6arm-PEG-NH2 (13.6%). Compared with the free enzyme, thermal, storage and operational stability of the immobilized HRP improved. The immobilized HRP still retained over 68.1% activity after being reused 8 times. These results suggest that the multi-armed magnetic composite has good application prospect for enzyme immobilization.

Highlights

Horseradish peroxidase (HRP) is a promising biocatalyst, and there are reports that it can be used for the removal of phenolic compounds, hormones, aromatic amines and the decolourization of textile wastewater [1,2,3]
The amino group of the support material and the amino group of the HRP were connected by glutaraldehyde to form an immobilized HRP
In this work we synthesized a novel type of the magnetic multi-arm nanocomposite Graphene oxide (GO)@Fe3O4@6arm-polyethylene glycol (PEG)-NH2 and applied it for the immobilization of horseradish peroxidase (HRP)

Summary

Introduction

Horseradish peroxidase (HRP) is a promising biocatalyst, and there are reports that it can be used for the removal of phenolic compounds, hormones, aromatic amines and the decolourization of textile wastewater [1,2,3]. In the presence of hydrogen peroxide, HRP can catalyze the oxidation of phenols to produce phenoxy radical. Graphene oxide (GO) is a two-dimensional nanomaterial with a thickness of only one atom. Because it is rich in surface groups and has a relatively large functional surface area with a unique double-sided structure, GO can be used as a support for biological macromolecules [11,12]. An enzyme immobilized on the GO cannot be recycled, but GO@Fe3O4 can be separated from the solution using an additional magnetic field. The hydrogen peroxide, GO and Fe3O4 can all catalyze the oxidation of peroxidase substrate 3,3,5,5-tetramethylbenzidine

Methods

Results

Conclusion