A Bienzymatic System Constituted by Horseradish Peroxidase and Glucose Oxidase for Phenol Contaminant Degradation

Glucose oxidase (GOx) and horseradish peroxidase (HRP) are the most frequently used enzyme pair to demonstrate the feasibility and advantages of multienzyme systems. The concept has therefore been developed, which is based on a simultaneous application of glucose oxidase and horseradish peroxidase. Starting with glucose as a substrate for glucose oxidase (GOx), hydrogen peroxide (H₂O₂) was generated in situ. Using the cascade reaction carried out by GOx and HRP as a model system, this study aimed to evaluate the chosen phenolic contaminant degradation efficiency by combining the biocatalytic activity of HRP with the combination of GOx. The bienzymatic system was characterized by determining the activity profile as a function of pH and temperature. The optimum pH value of the enzyme activity was found as 5. The temperature profile of the bienzymatic system of GOx-HRP exhibited higher relative activity at 30 °C. Finally, the bienzymatic system of GOx-HRP was tested for the degradation of three model phenolic contaminants, which were Acetaminophen (APAP), Bisphenol A (BPA), and 2,4-Dichlorophenol (DCP). The enzymatic reaction was able to reach over 80% for APAP degradation, and almost complete removal for both BPA and 2,4-DCP. The peroxidases are enzymes that unfortunately inactivated rapidly at H₂O₂ concentrations. This study also showed the low degradation efficiencies of phenolic contaminants were observed at 3mM H₂O_2. The result shown that the combination of GOx-HRP could reduce the issue of inactivation of HRP at H₂O₂-dependent oxidation for phenolic contaminant degradation. These findings demonstrated that bienzymatic system of GOx-HRP mediated oxidative coupling reaction can potentially serve as an alternative strategy to degrade certain phenolic contaminants in water/wastewater treatment.