Thermophilic bioremediation of recalcitrant emerging pollutants: A novel application of the fungal DyP from Pleurotus sapidus

Abstract

Dye-degrading peroxidases (DyPs) are increasingly finding applications in biotechnology owing to their broad substrate specificity and potential ability to degrade recalcitrant organic dyes and emerging pollutants. The presence and accumulation of emerging pollutants (EPs) in water sources poses a pressing health and environmental issue that necessitates the development of greener and more economical remediation approaches such as biological remediation. The present study explores the potential application of a recombinant thermophilic DyP from Pleurotus sapidus, rPsaDyP, in simultaneously degrading a structurally diverse panel of ten EPs as analysed by LC-MS/MS. The enzyme showed high efficiency (>90 %) at degrading four contaminants at room temperature, with notably enhanced remediation performance at 60 °C, including degradation of two additional EPs, achieving significant degradation of meloxicam, 2-mercaptobenzothiazole (MBT), furosemide, paracetamol, caffeine, and roxithromycin. Analysis of the transformation products produced during rPsaDyP-mediated degradation of meloxicam revealed a high degree of commonality in the products generated from biological, chemical, and photochemical treatment. Lastly, rPsaDyP treatment was shown to significantly reduce the toxicity of paracetamol on lettuce seeds in phyto-toxicological assays. These findings represent a novel application of elevated temperature degradation of EPs using thermostable recombinant peroxidases (such as rPsaDyP) for wastewater remediation.