Low-density polyethylene (LDPE) film degradation potential of marine fungi isolated from microplastics, beach sand, and coastal seawater

Plastic pollution, resulting from the widespread use of plastics, their high production volumes, their ability to remain in the environment for long periods without decomposing, is one of the most significant global environmental problems, negatively impacting ecosystems, biodiversity, and human health. This study aimed to isolate marine fungi associated with microplastics, beach sand, and coastal seawater and evaluate their potential to modify low-density polyethylene (LDPE) under laboratory conditions. In total, 30 fungal isolates were obtained from beach sand, coastal seawater, and microplastic particles collected from the coastal area of Kuşadası, Aydın Province. The potential of the isolated fungi to modify LDPE was evaluated, and four fungal isolates were identified as potential PE-modifying candidates. The effects on LDPE were assessed using gravimetric weight loss measurements. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analyses were performed on the LDPE films after fungal treatment. After 45 days of incubation, the highest observed gravimetric weight loss was recorded for the following fungal species: Cladosporium sp. HBF380, Paradendryphiella sp. HBF381, Stemphylium sp. HBF384, and Didymella sp. HBF383, respectively. During the LDPE modification by Cladosporium sp. HBF380, which showed the highest degradation potential, FTIR and SEM were used to understand the changes on the LDPE film surface. LDPE modification was assessed using gravimetric weight-loss measurements, supported by FTIR and SEM observations. The isolate demonstrated the potential to modify LDPE under laboratory conditions. The study identifies marine fungal isolates associated with measurable physicochemical changes in LDPE and demonstrates their potential as candidates for further research on LDPE biodeterioration and biodegradation.