BIODEGRADATION OF EXPANDED POLYSTYRENE USING PSEUDOMONAS AERUGINOSA VITARK5

Polystyrene, a widely used thermoplastic, polluting the environment in the form of micro/nanoplastics. Though traditional methods are commonly employed for plastic management, microbial degradation remains a more promising and eco-friendly approach. The present study focused on the biodegradation of expanded polystyrene (EPS) using microbes isolated from plastic-contaminated sites and assessing the degradants for their industrial importance. An isolate, VITARK5, was able to grow well in Bushnell Haas agar containing EPS as the only carbon source and was chosen for biodegradation studies. With robust glycolipid biosurfactant synthesis and biofilm formation, VITARK5 was identified to be Pseudomonas aeruginosa. In order to study biodegradation, VITARK5 was inoculated in Bushnell Haas broth containing thin EPS film and incubated at 37°C and 120 rpm for two weeks. After biodegradation, gravimetric analysis showed a 14.53% weight reduction of EPS film compared to the control. Formation of cracks and rough surfaces was observed on the film under scanning electron microscopy. GCMS analysis showed the presence of industrially important chemicals such as valerenol, 3-hydroxyl, 4-methoxy benzaldehyde, oxalic acid, dodecane, azacyclododecane and hexadecane. FTIR spectroscopy confirmed the presence of functional groups associated with the EPS and its additives. Biofilm formation and biosurfactant production synergistically would have promoted biodegradation. The findings of the present study suggest that the isolate P. aeruginosa sp.VITARK5 may be used in bioremediation for polystyrene degradation and valorisation to achieve circular bio-economy.