Colonization and Degradation of Thermally Oxidized High-Density Polyethylene by Aspergillus niger (ITCC No. 6052) Isolated from Plastic Waste Dumpsite

Plastic materials, particularly polyethylene, are the potential source of environmental pollution. In the present study, a fungal strain was isolated from plastic waste dumpsites capable of adhering to high-density polyethylene (HDPE) surface. The fungal strain was identified as Aspergillus niger (ITCC no. 6052). A visible increase in the growth of the fungi was observed on the surface of the polyethylene when cultured in minimal medium at 30 degrees C and 120 rpm, for 1 month. Approximately 3.44% reduction (gravimetrically) in mass and 61% reduction in tensile strength of polyethylene was observed after 1 month of incubation with fungal isolate. Scanning electron microscope analysis showed hyphael penetration and cracks on the surface of polyethylene. A thick network of fungal hyphae forming a biofilm was also observed on the surface of the plastic pieces. The efficient biofilm formation on polyethylene surface by Aspergillus niger (ITCC no. 6052) is attributed to its high cell surface hydrophobicity. This study indicated that Aspergillus niger (ITCC no. 6052) has ability to degrade thermally oxidized polyethylene.