Mechanistic study of a diazo dye degradation by Soybean Peroxidase

Background: Enzyme based remediation of wastewater is emerging as a novel, efficient and environmentally-friendlier approach. However, studies showing detailed mechanisms of enzyme mediated degradation of organic pollutants are not widely published.Results: The present report describes a detailed study on the use of Soybean Peroxidase to efficiently degrade Trypan Blue, a diazo dye. In addition to examining various parameters that can affect the dye degradation ability of the enzyme, such as enzyme and H₂O₂ concentration, reaction pH and temperature, we carried out a detailed mechanistic study of Trypan Blue degradation. HPLC-DAD and LC-MS/MS studies were carried out to confirm dye degradation and analyze the intermediate metabolites and develop a detailed mechanistic dye degradation pathway.Conclusion: We report that Soybean peroxidase causes Trypan Blue degradation via symmetrical azo bond cleavage and subsequent radical-initiated ring opening of the metabolites. Interestingly, our results also show that no high molecular weight polymers were produced during the peroxidase-H₂O₂ mediated degradation of the phenolic Trypan Blue.