In the framework of unremitting efforts to preserve our planet from industrial wastes, this study aims to develop a cheap and efficient biocatalyst for the ecofriendly treatment of dye wastewater. Particularly, packaging waste of expanded polystyrene foam (EPS) was crushed into uniform spheres and easily coated with a layer of the bio-adhesive polydopamine. The successful coating of EPS spheres with a layer of polydopamine was characterized by ATR-FTIR spectroscopy. The polydopamine layer acted as an active platform allowing the covalent immobilization of horseradish peroxidase (HRP) via Schiff base or Michael addition reaction. The immobilization efficiency was about 46%. The immobilized HRP could retain 53% of its activity at high pH (pH 10) however, the reactivity of free HRP was dramatically reduced to 25 %. The immobilized HRP showed remarkable tolerance towards elevated temperature (60 °C) and recorded a higher activity of about 95 % compared to 56 % of free HRP. This in turn makes it a suitable biocatalyst for decolorization of industrial dye wastewater that is typically hot. The immobilized HRP could achieve almost complete decolorization of crystal violet dye within 120 min. Furthermore, the immobilized HRP can be easily separated by skimming and reused for ten cycles with a minimum decolorization efficiency of about 80 % and it can even achieve 60 % of decolorization efficiency after 15 times reuse. Overall, this study constituted the transformation of packaging polystyrene foam waste into an efficient biocatalyst that can be used for the enzymatic treatment of dye wastewater.