Sustainable Removal of Nanoplastics: Exploiting the Lipolytic Activity of Pseudomonas aeruginosa O6 Isolated from Mariout Wetland, Egypt

The increasing problem of micro-nano plastic pollution in Egypt's coastal areas is a global threat to marine ecosystems. This study investigated an environmentally friendly bioremediation approach to tackle this issue, specifically looking at the identification and application of lipolytic bacteria found in plastic-polluted regions for breaking down nanoplastics. One of the seven bacterial strains examined showed an exceptional efficacy in degrading nanoplastics. This strain was identified as Pseudomonas aeruginosa using 16S rRNA gene sequencing and was recorded in the NCBI database with an accession number of PP087224. The strain was analyzed using a p-nitrophenyl palmitate assay to quantify its lipase production when exposed to different nanoplastics, such as polyethylene, polystyrene, and polyethylene terephthalate. The results showed notable differences in enzyme activity depending on the polymer type. The strain exhibited the highest lipase activity with polyethylene (142± 2U/ µL), followed by polystyrene (83± 1.4U/ µL), and the lowest activity was observed with polyethylene terephthalate (22± 2U/ µL) compared to the control. The study showed that the bacterial reaction to nanoplastic pollution differs depending on the polymer type. Scanning electron microscopy verified a 97% decrease in nanoplastic sizes and chemical structural changes. This was validated by Fourier transform infrared spectroscopy (FTIR) and X-ray differential (XRD) analysis, which showed modifications in the polymer's chemical structure and crystallinity. The research introduced a viable approach for nanoplastic remediation using particular bacterial strain and their enzymes, providing a new solution to the urgent problem of marine nanoplastic pollution utilizing the capabilities of Pseudomonas aeruginosa O6.