Decolorization of dye effluents via immobilized glycoprotein peroxidase on post-consumer polystyrene foam

Development of sustainable approaches to manage industrial wastes such as plastic waste and dye effluents is a major research endeavor, owing to escalating environmental and health concerns arising from discharge of such wastes into water bodies. In this context, this study aims to convert packaging waste of expanded polystyrene foam (EPS) into effective biocatalyst for enzymatic degradation of dye effluent. Briefly, crushed EPS were decorated with amine groups via chlorosulfonation followed by conjugation of branched polyethylenimine. Carbohydrate rich turnip peroxidase (TPOD) was purified to homogeneity from Brassic rapa roots followed by periodate oxidation to introduce reactive dialdehyde groups. Such oxidized TPOD glycoprotein was covalently immobilized on aminated EPS through Schiff base formation. Immobilized TPOD exposed noticeable tolerance toward elevated temperatures (80 °C) that qualifies it as viable biocatalyst for decolorization of dye effluents that is frequently hot. Indeed, immobilized TPOD could successfully decolorize methyl orange (90 %) and crystal violet (96 %) within 2 h. Due to the floating nature of EPS, the immobilized TPOD was simply separated by skimming and reused in fifteen subsequent catalytic cycles. Ultimately, this work demonstrates the conversion of post-consumer EPS into a value-added biocatalyst for the ecofriendly enzymatic treatment of dye effluents.