Fungal-mediated deterioration and biodegradation study of low-density polyethylene (LDPE) isolated from municipal dump yard in Chennai, India

Abstract

Low-density polyethylene (LDPE) is a conventionally used polymer and possesses diverse applications in various industries due to its low cost, excellent strength, and numerous mechano-thermal properties. Unfortunately, the deliberate and unconscious release of excess polythene in the environment causes serious ecological threat. To deal with this issue, biodegradation of LDPE was considered using different fungal strains, namely Aspergillus flavus, Aspergillus versicolor, and Fusarium solani isolated from local municipal dump yard in Chennai, India. For degradation study, the polymers were subjected to microbial cultures for 60 days under laboratory conditions. The extent of the degradation was quantified in terms of the weight loss of the LDPE films, pH changes of the culture medium, mineralization, and analysed by field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR) spectroscopy. FESEM micrographs revealed the fungal colonization on the polythene matrix due to their metabolic activities, whereas FTIR spectra showed the changes in chemical nature of the polymer films and confirmed the biodegradation of LDPE. By comparing the reduction in dry weight of LDPE strips and Sturm test results, A. versicolor strain was found to be a potential LDPE-degrading candidate than A. flavus and F. solani and, hopefully, can address the global issue of polymer pollution.