Biodegradation of Low-Density Polyethylene (LDPE) Plastic by Staphylococcus spp. Isolated from Waste Disposal Sites in Urban Peshawar, Khyber Pakhtunkhwa, Pakistan

Background: Polyethylene (PE), a polymer of ethylene, comprises of long chain backbone of carbon atom and hydrogen, which are linked covalently to each other and are derived from petrochemicals. Polyethylene is widely used due to its low cost, ease of production, versatility and durability. Aims: The current research study explores biodegradation of low density polyethylene by Staphylococcus species, isolated from various site of waste disposal in District Peshawar. Methodology: In this Experimental study, a total of 20 soil samples were collected using a sterile forceps from 5-15 cm depth at various trash disposal sites in Peshawar and transported in sterile zipper bags to Department of health sciences, City University Peshawar. A stock solution was made by dissolving 1 gram of soil samples in 9 mL of sterile distilled water. To get pure bacterial isolates, serial dilutions was carried out and inoculated on mannitol salt agar (MSA) media, followed by sub-culturing. Films were heat treated at 70oC for 10 days and were further irradiated with Ultra Violet rays (365nm). Using a sharp blade these films were sliced into 2/2cm 2 pieces. Each film was further treated with heat at 70°C for 250 hours. Results: The initial weight of plastic was 0.00745, while weight of these plastic after 90 days was recorded 0.08577 after loss with carbonyl index of 0.8686. Conclusion: It was found that various species of Staphylococcus could attach to and helps to partially degrade plastic films, as confirmed through weight loss and various analytical techniques like XRD, FE-SEM, FTIR and total carbon analysis. The study observed surface damage to plastic films and a slight reduction in total carbon, which indicates slow and surface-confined biodegradation.