Biodegradation of polyethylene by Gordonia sp. C1 and Bacillus sp. C2 isolated from landfill

Polyethylene (PE), one of the most widely used petroleum-derived polymers, has led to persistent environmental accumulation of plastic waste, posing a pressing global challenge. Biodegradation offers a promising solution to mitigate PE pollution, yet efficient microbial degraders remain scarce. In this study, we report the isolation of two novel bacterial strains, Gordonia sp. C1 and Bacillus sp. C2, from landfill-derived plastic waste, with Gordonia sp. C1 representing the first discovery of its kind for PE degradation. Both strains demonstrated the ability to degrade low molecular weight low-density polyethylene (LDPE) powder and commercial PE mulch films. Comprehensive analyses, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA), 13C NMR, thermogravimetric analysis, and high-temperature gel permeation chromatography (HT-GPC), revealed significant deterioration of PE films, characterized by surface cracks, increased hydrophilicity, reduced weight-average molecular weight, and decreased thermal stability. The carbonyl indices of LDPE powder degraded by C1 and C2 for 60 days reached 0.36 and 0.26, respectively, with similar degradation observed in PE films. The appearance of quaternary carbon and increased C=O groups in treated PE indicated microbial oxidation and oxidative cleavage of carbon-carbon bonds. These findings highlight the potential of Gordonia sp. C1 and Bacillus sp. C2 as efficient PE degraders, offering a sustainable approach for bio-recycling and managing PE plastic waste.