Influence of ultraviolet and chemical treatment on the biodegradation of low-density polyethylene and high-density polyethylene by Cephalosporium strain

In the present work, the potential of Cephalosporium strain in degrading the pre-treated (ultraviolet irradiation followed by nitric acid treatment) low-density polyethylene and high-density polyethylene films was investigated. Our observations revealed a significant weight reduction of 24.53 ± 0.73% and 18.22 ± 0.31% in pre-treated low-density polyethylene and high-density polyethylene films respectively, after 56 days of incubation with the Cephalosporium strain. Changes in the physicochemical properties of the mineral salt medium (MSM) were studied to assess the extent of biodegradation. The pH of the MSM decreased gradually during the incubation period, whereas its total dissolved solids and conductivity values increased steadily. Fourier transform infrared spectroscopy (FTIR) indicated the formation of hydroxyl and C = C groups in biodegraded low-density polyethylene films, while in the case of biodegraded high-density polyethylene films it indicated the -\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$-$$\end{document}CH2 stretching. Furthermore, the thermogravimetric analysis (TGA) revealed an enhancement in the thermal stabilities of both the LDPE and HDPE films post the biodegradation. Modifications in the polymer surface morphologies after UV irradiation, chemical treatment, and biodegradation steps were visualized via scanning electron microscopy (SEM) analysis. All our observations confirm the ability of the Cephalosporium strain in biodegrading the pre-treated LDPE and HDPE films.