The Role of Plasmid-Mediated Bacteria in the Biodegradation of Low-Density Polyethylene in Mitigating Climate Change

Polyethene causes pollution and global warming not only because of the increase in the problem of waste disposal and landfilling but also because it releases carbon(iv)oxide and dioxins due to burning, which hurts the climate. Recent studies have shown that biodegradation using plasmid prosessing bacteria (PPB) could help prevent environmental damage from pollution and reduce carbon footprint and greenhouse gas emissions from polyethene usage. This study assayed the low-density polyethylene degrading potential of PPB assayed from polyethylene-polluted sites. Soil samples and waste sachet water bags, popularly called 'pure water', were collected from a polyethene dumpsite near Ekiti State University. These samples were analysed for bacterial loads and polyethene degrading PPB using nutrient agar and mineral salt medium, respectively. The biodegradation of low-density polyethene using sachet water films was observed spectrophotometrically using the broth culture of the bacterial isolates for 30 days on a mineral salt medium. The bacteria were identified based on molecular characterisation using 16S RNA sequencing. Six bacterial isolates identified from polyethene polluted sites include: Lysinibacillus xylanilyticus strain BN-13 (S6), Rhodopseudomonas palustris strain KRPR02 (W5), Pseudomonasaeruginosa strain JAY (N2), Stenotrophomonas maltophilia strain T7D7, Pseudomonas aeruginosa strain SMVIT-1 (S1) and Achromobacter xylosoxidans YEB (W11), and four isolates were observed to have the presence of plasmid after analysis. The four isolates were used to degrade the PE films, which peaked at degradation on the 21 days, followed by a gradual declination on the 28 days. L. xylanilyticus strain BN-13(S6) exhibited the highest degradation of 0.898 nm, and A. xylosoxidans strain YEB (W11) exhibited a minor degradation of 0.788 nm. The result revealed that PPBs are competent biodegrades of polyethene wastes and can be used as a better approach to restoring polyethene and mitigating climate change.