Biodegradation of low-density polyethylene (LDPE) bags using fungal isolates from Gondar municipal solid waste disposal soil

Low-density polyethylene (LDPE) poses a significant environmental threat due to its resistance to degradation. The present study screened and evaluated the fungal isolates obtained from the soil of the Gondar City municipal solid waste disposal site for the degradation of low-density polyethylene bags. The fungal isolates were isolated using mineral salt media supplemented with polyethylene powder. They were identified by microscopic examination, cultural characteristics and ITS1 and ITS2-region sequencing. The isolates’ capacity to produce extracellular enzymes was examined on different substrates. The degree of biodegradation on polyethylene films was evaluated through the weight loss method and Fourier transform infrared spectroscopy. After 45 days of incubation in 25 and 40-micron-thick polyethylene films, respectively, isolate TA3 (46.57 ± 0.05% and 22.25 ± 0.09%) showed the highest degradation, followed by TA2 (26.02 ± 0.1% and 16.37 ± 0.12%) and TA1 (23.28 ± 0.08% and 14.1 ± 0.03%). These isolates exhibited lipase and esterase activity. Only the TA1 isolate showed the laccase enzyme. Fourier transform infrared spectroscopy analysis revealed the appearance and disappearance of functional groups on the surface of polyethylene films, which were linked to hydrocarbon degradation. Isolate TA1 is identified as the Aspergillus tubingensis strain, and TA2 and TA3, are affiliated with the Aspergillus fumigatus, and Aspergillus niger, respectively. Overall, TA3 had excellent capacity for low-density polyethylene degradation. Further research is required to improve the degradation ability of potential isolates by evaluating optimum conditions for enzyme production, thereby recovering enzymatic activity for environmental applications in plastic waste bioremediation.