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 • 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.
Chitosan/poly(vinyl alcohol) (CS/PVA) blend membranes were prepared using the casting method and their physiochemical properties were analyzed using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FTIR and XRD demonstrated possible hydrogen bonds between CS and PVA. The addition of PVA to CS resulted in surface roughness as analyzed by SEM. The CS/PVA blend membrane exhibited high tensile properties (81.62%) and reduced water-holding capacity (53.8%) compared to a pure CS membrane (control). Cell viability and proliferation were assessed via an MTT assay with Vero cell culture. Associated with improved physicochemical properties, the CS/PVA blend membrane promotes cell proliferation of Vero cells with high specific growth rate (0.582 day -1 ). The results demonstrate that the blending of CS and PVA could significantly alter the surface rugosity, water-holding capacity and improve the mechanical and biological properties of the membrane. Interestingly, this concept can be extended for different anchorage-dependent cell lines, as an alternative carrier material.
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