Biodegradation of polyethylene by indigenous fungi from waste recycling site, South West, Nigeria

Abstract

Indiscriminate disposal of polyethylene materials has become a regular practice among developing nations of Africa, especially in Nigeria. This has resulted in environmental pollution; hence, this study investigates the microbial degradation of polyethylene obtained from a polyethylene dumpsite in South West, Nigeria, under static in vitro condition. Soil samples were analysed for mineral composition and physicochemical characteristics. The fungal isolates were screened for polyethylene degradation using minimal salt medium containing polyethylene as sole source of carbon and nitrogen for their ability to degrade polyethylene. Gravimetric analysis and Fourier-transform infrared spectroscopy (FTIR) were used to monitor the biodegradation of the polyethylene. Aspergillus flavus, A. nidulans, Penicillium chrysogenum, Mucor mucedo, Eurotium repens, A. fumigatus and Rhizopus stolonifer were enumerated. Mean microbial count ranged from 1.37 × 107 to 8.2 × 108 SFU/g. Individual weight loss was observed in the polyethylene strip cultured with P. chrysogenum (1%), E. repens (1%) and A. nidulans (2%). The changes observed in the FTIR spectra especially the polyethylene sample inoculated with A. nidulans confirm the significant role of fungi in polyethylene degradation. Hence, its usage in the treatment of polyethylene in the environment is a cheap eco-friendly alternative. Aspergillus nidulans, E. repens and P. notatum play significant roles in the biodegradation of polyethylene which necessitates incorporating in polyethylene products waste management to foster a cleaner environment.