Determination of the role of <i>Dermococcus nishinomiyaensis</i> and <i>Pseudomonas aeruginosa </i>in polyethylene (PE) and polyethylene terephthalate (PT) biodegradation

Plastic pollution is a worldwide menace to the ecosystem and human health, and only less than 10 percent of the plastic waste has been recycled and its continued existence causes climate change. The purpose of the study was to test the potential of biodegradation of Dermococcus inshinomiyaensis on two common types of plastics (Polyethylene Terephthalate (PET) and Polyethylene (PE)) when compared to the established degrader, Pseudomonas aeruginosa, at conditions that simulated the natural environment. The biodegradation was evaluated in terms of biofilm biomass determination, relative weight loss, scanning electron microscopy (SEM), and Fourier-transform infrared (FT-IR) spectroscopy. Biofilm quantification showed that D. inshinomiyaensis formed stronger biofilms on PET bottles (absorbance 0.16) than on PE bags (0.10–0.12), with activity comparable to that of P. aeruginosa. The analysis of weight loss showed that PE was severely degraded by D. inshinomiyaensis (12.2%), P. aeruginosa (40%), and PET was not severely degraded (0.7%). FT-IR spectra of PE indicated new absorption bands beyond 400 cm-¹, confirming structural defects induced by microbial activity. Distinct peaks between 1600–2653 cm-¹, including 1639 and 1737 cm-¹ for P. aeruginosa and 1981–2325 cm-¹ for D. inshinomiyaensis, suggested the formation of novel intermediates. SEM analysis also showed intense deformations in PE using D. inshinomiyaensis so that it generated a wide range of cracks, wrinkles, and grooves, which were much more effective compared to the action of P. aeruginosa.These results demonstrate the novelty of D. inshinomiyaensis as a potential biodegrader of PE, as it provided potential use in the management of plastic waste in a sustainable environment.