Sustainable biocatalyst for textile dye effluent treatment using immobilized turnip peroxidase on polydopamine coated sawdust

Immobilizing enzymes on sustainable supports enhances wastewater treatment efficiency and promotes environmental sustainability. This study investigates polydopamine-coated sawdust as a sustainable support for immobilizing turnip peroxidase (TP) to mitigate textile dye effluent pollution. Sawdust was dip-coated with a bio-adhesive polydopamine layer, facilitating covalent TP immobilization. The TP was isolated and purified to homogeneity from the roots of Brassica rapa . Compared to free TP, the immobilized enzyme exhibited improved thermal and pH stability and was reusable for 25 consecutive catalytic cycles. Furthermore, it demonstrated synergistic potential for decolorization of fast green FCF (72 %) and crystal violet (88 %) dyes within 120 min through adsorption and catalytic enzymatic oxidation. Eventually, immobilization of TP on sustainably sourced and cost-effective polydopamine-coated sawdust has the potential to serve as an efficient biocatalyst for eco-friendly enzymatic remediation of dye-contaminated wastewater. • Polydopamine-coated sawdust serves as a sustainable enzyme immobilization support. • Turnip peroxidase (TP) immobilized for enzymatic decolorization of dye effluents. • Immobilized TP shows superior tolerance to high temperature and pH versus free TP. • Immobilized TP combines adsorption and enzymatic oxidation for dye decolorization. • Immobilized TP retains efficiency over multiple reuse cycles for dye decolorization.