Enhanced Synergistic Plastic Breakdown via Antifungal Laccase from White Rot Fungi and Cerium Oxide Nanoparticles (CeO₂-NPs)

Plastic pollution is a major environmental challenge, demanding innovative biodegradation solutions. This study explores the multifunctional potential of fungal laccases through comparative enzyme production, antifungal biocontrol, and synergistic polyethylene degradation using cerium oxide nanoparticles (CeO₂-NPs). Three white-rot fungi were screened via guaiacol assay, with Trametes versicolor identified as the highest laccase producer, followed by Pleurotus ostreatus and Ganoderma lucidum. Laccase from P. ostreatus was purified using ammonium sulfate precipitation and dialysis, showing a UV-visible peak at 231 nm and minimal contamination. Purified laccase exhibited higher catalytic efficiency than the crude extract, reaching 1107 U/L at 40°C and 1768 U/L at pH 4, with reduced activity in neutral-alkaline conditions. Antifungal assays revealed species-specific effects: Aspergillus flavus showed non-linear inhibition (39.85% at 100 ppm), Alternaria solani showed dose-dependent suppression (up to 19.00% at 400 ppm), and Fusarium sp. exhibited low susceptibility (11.23% inhibition max). Laccase-CeO₂-NP composites achieved synergistic polyethylene degradation, confirmed by FTIR analysis indicating Amide I bands (1650 cm⁻¹), C–H stretching shifts, and disrupted polymer packing. Gravimetric analysis showed >85% weight loss in white polyethylene after 90 days, outperforming typical laccase-only degradation (20–40%). The enhanced performance was attributed to nanoparticle-facilitated surface oxidation, improved enzyme accessibility, and catalytic electron transfer. These findings highlight laccase–nanoparticle composites as promising dual-function agents for agricultural biocontrol and plastic bioremediation.

• Research Project