Screening of Fungal Isolates for Biodegradation Potentials of Low-Density Polyethylene from Selected Dumpsites

Abstract

Polyethylene is the most commonly used synthetic plastic and poorly degraded in natural environments. This study was designed to evaluate biodegradation potentials of low-density polyethylene by fugal isolates from Station Market, Kaduna State, Nigeria. Soil samples were collected at a depth of 20cm using a sterilized hand towel and taken to microbiology laboratory, Kaduna State University. Fungi were isolated and each colony was repeatedly sub-cultured on freshly prepared SDA to obtain pure isolates. Pure separated single colonies were maintained on sterile slants at 4˚C for further investigation. Low-density polyethylene (LDPE) sheets were cut into bits and immersed in xylene and boiled for 15 minutes to dissolve and crushed. The LDPE powder was added to a mineral salt medium (MSM) containing salts in 1liter of distilled water after which the fungal isolates were introduced. Scanning electron microscopy and Fourier- Transform Infrared Spectroscopy (FTIR) analysis were used to determine the changes in the polymer bond of LDPE sheet after the biodegradation. The findings shows that Aspergillus niger, Aspergillus flavus, Brown rot and White rot fungi showed 21.1%, 16.1%, 17.6%, and 18.3% reductions in the polyethylene discs after incubation respective. Therefore, the study concludes that fungal species play a significant role in the degradation of LDPE and can be used in future studies for the degradation of complex plastic materials. Finally, the study recommends that Aspergillus niger and Aspergillus falvus be considered as potential candidates to degrade LDPE.