Application of engineered heme enzymes based on myoglobin with high peroxidase activity for efficient degradation of various emerging pollutants

Emerging pollutants in the aquatic environment from pharmaceutical and personal care products (PPCPs) attract much attention due to their environmental risk and toxicological properties, posing a threat to human health and safety. In this study, we fulfilled the direct and efficient degradation of PPCPs (i.e. diclofenac sodium, 2-mercaptobenzothiazole, paracetamol, and furosemide) using engineered H2O2-dependent heme enzymes based on myoglobin (Mb) with high peroxidase activity. Especially, the triple mutant F43Y/P88W/F138W Mb could efficiently degrade diclofenac sodium, 2-mercaptobenzothiazole, paracetamol, and furosemide with a degradation rate of ∼98.5%, ∼99%, ∼98%, and ∼91%, respectively. These activities are much higher than other reported native enzymes, such as laccase and horseradial peroxidase. As further analyzed by ESI-MS, we identified multiple degradation products of those four contaminants and thus proposed possible degradation mechanisms. This study indicates that enzyme-based degradation of emerging pollutants is a promising environmental remediation approach.