Surface-level microbial-assisted biodegradation of polyolefin thermoplastics for enhanced energy efficiency and emission reduction

Polyolefins are versatile thermoplastic polymers widely used in packaging, automotive, textiles and consumer goods. Traditional disposal methods cause persistent polymer waste accumulation with minimal biodegradation. Existing thermal recycling processes, though effective, are energy-intensive and emit harmful gases, posing significant environmental challenges. This study introduces efficient microbial surface biodegradation techniques for polypropylene and polyethylene polymers using three fungi species: Engyodontium album , Aspergillus tamarii , and Aspergillus niger. Three waste sources – car components, cloth fabric, and garbage bins - demonstrated the technique's efficiency across varied surface morphologies and chemical compositions. The proposed cyclical microbial degradation process enables effective polymer breakdown, achieving up to 7.3 % weight loss in car components after 12 days of treatment. The eco-friendly pretreatment improves microbial accessibility, and together with microbial surface biodegradation operating at lower temperatures, this method significantly reduces energy consumption and minimises emissions of harmful volatile organic compounds compared to thermal recycling. Key findings also underscore the fungi's role: Aspergillus species demonstrate enhanced surface modification with oxygen content increasing to 16.39 %, while E. album exhibited the higher nitrogen incorporation (6.03–8.01 %). The proposed process maintains stable microbial activity and enhances degradation efficiency. These results position microbial degradation as a scalable, low-energy, and environmentally responsible step for polyolefin recycling. • Novel microbial surface biodegradation was proposed for polyolefin thermoplastics. • Eco-friendly acid and UV pre-treatment enhances fungal degradation of polyolefins. • Surface microbial degradation efficiently led to 7.3 % weight loss in 12 days. • Aspergillus enhances oxidation, while Engyodontium increases surface nitrogen.