Biodegradation of Ultra-violet Irradiated Waste Polyethylene Bags by Bacterial Community from Soil around Coal -fired Thermal Power Plant

Abstract

The current study focused on biotic degradation of waste polyethylene bags using bacterial community from hydrocarbon contaminated soil near coal fired thermal power plant and also the effect of UV irradiation on its biodegradation.The predominant groups in the bacterial community in the hydrocarbon contaminated soil near coal fired thermal power plant were identified by 16s DNA sequencing were Steroidobacter, Flavisolibacter, Planctomyces, Balneimonas, Gemmata, Alicyclobacillus, Lactobacillus, Mycobacterium, Geodermatophilus, Prevotella, Virgisporangium and Adhaeribacter. The native bacterial community from hydrocarbon contaminated soil was capable of polyethylene degradation.The bacterial community in the hydrocarbon contaminated soil metabolized 12.85± 0.16 percent of polyethylene (10 g/L) as sole carbon source in mineral salt media within 30 days.The UV irradiation of polyethylene enhanced weight loss of 22.80 percent higher than untreated polyethylene. The improvement in bacterial degradation by UV exposure of waste polyethylene in-vitro for 144 hresulted 15.78± 0.32 percent weight loss in 30 days. The photo-oxidation by UV irradiation of polyethylene had surface disruption and was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The photochemical reaction induced by UV irradiation of polyethylene resulted in formation of carbonyl peaks on polymer surface and addition as well as shifting of peaks. The morphological changes of polyethylene by UV exposure enhanced colonization, metabolism by and synergistic effect on polyethylene biodegradation by bacterial community from hydrocarbon contaminated soil.