Horseradish peroxidase immobilization by copolymerization into cross-linked polyacrylamide gel and its dye degradation and detoxification potential

Owing to the ever-increasing environmental and health impacts associated with the discharge of dye-based effluents, effective remediation of industrial waste have become a top priority for the industrialists and environmental fraternity, around the world. Plant-based peroxidases represent a suitable bio-remediating agent for the effective treatment of original dyes or dye-based colored wastewater effluents. In the present study, horseradish peroxidase was immobilized by copolymerization into cross-linked polyacrylamide gel and investigated its potential for the degradation and detoxification of an azo dye, methyl orange. In the presence of N, N′-methylenebisacrylamide as a cross-linker, polyacrylamide gel at 10% concentration furnished >80% of immobilization yield. The surface morphology of the control (free enzyme) and immobilized enzyme, i.e., horseradish peroxidase cross-linked polyacrylamide gel was characterized using scanning electron microscopy. The high yielded horseradish peroxidase cross-linked polyacrylamide gel concentration, i.e., 10% was used to develop a packed bed reactor and exploited for dye degradation and detoxification purposes. A noteworthy level (>90%) of dye degradation was recorded after polyacrylamide gel cross-linked horseradish peroxidase-catalyzed reaction in a packed bed bioreactor. The biodegradation was further assessed by Fourier-transform infrared spectral analysis. The acute toxicity assays demonstrated that enzyme-based bio-degradation might be used effectively for large-scale environmental remediation of dyes and dyes containing wastewater effluents.