Comparative evaluation of polyethylene degradation efficiency by two Pseudomonas aeruginosa strains from urban waste...

The widespread use and environmental persistence of polyethylene (PE) have led to a global pollution crisis, which is intensified by its fragmentation into hazardous micro- and nanoplastics. Although bioremediation using polymer-degrading microbes presents a sustainable alternative, only a limited microbes have been identified, primarily due to the challenges of culturing potential degraders in the laboratory. We isolated two P. aeruginosa strains (SKD-SD-3171 and SS-SD-7780) from urban waste disposal areas and comparatively evaluated their PE degrading efficacy, over 120 days. Both strains utilized PE as a carbon source, as confirmed by weight loss (24.53±0.35% for P. aeruginosa SKD-SD-3171 and 22.50±0.35% for P. aeruginosa SS-SD-7780), polymer reduction rate (K=0.00235 day^-1±0.00004 for P. aeruginosa SKD-SD-3171 and 0.00212 day^-1±0.00004 for P. aeruginosa SS-SD-7780), and calculation of half-life (t1/2=295.55±4.77 for P. aeruginosa SKD-SD-3171 and 326.39±5.94 for P. aeruginosa SS-SD-7780) after the incubation in a carbon-free medium. Biodegradation was further validated using fourier transform infrared spectroscopy (FT-IR), which showed structural alterations, and field emission scanning electron microscopy (FE-SEM), which revealed surface erosion in PE, following microbial treatment. Additionally, gas chromatography-mass spectrometry (GC-MS) identified degradation intermediates whose kinetic profiling revealed effective polyethylene degradation through biodegradation efficiency metrics. Our findings demonstrate that P. aeruginosa SKD-SD-3171 exhibits comparatively faster and consistent polyethylene degradation kinetics than P. aeruginosa SS-SD-7780 under laboratory-based conditions and it also establishes effective methodological framework for isolation, selection and evaluation of specific polymer-degrading microorganisms using advanced analytical techniques. These findings provide insights into developing PE-waste management strategies like enzyme characterization, followed by field-scale validation to enhance degradation kinetics.