S89: ENHANCED RATE OF FUNGAL Biodegradation of Polyurethane under compostING CONDITIONS

Composting is a natural process involving the aerobic decomposition of organic waste by a mixed microbial population that goes through a range of temperature changes due to the heat generated by the growth of microorganisms. Historically, a major portion of municipal solid waste has been directed towards landfill, resulting in the scarcity of available sites with plastics representing a major component. A promising alternative for some plastics might be through municipal composting rather directing them to landfill sites. In this study, we examined the rate of biodegradation of the polyurethane (PU), in collaboration with the TEG Group Plc, based at Todmorden, UK.  The PU sheets after 4 weeks of burial under compost were analysed for the physical and chemical degradation by tensile strength and FTIR respectively. Tensile strength (stress that plastic withstands before necking while being stretched) decreased >75% and Scanning Electron Microscopy showed extensive pits and holes in the sheet whereas controls showed only a approx. 20% loss in tensile strength after 12 weeks. Culture dependent and independent techniques were used to study the diversity of fungal population taking part in the biodegradation process and revealed a significant increase in the fungal population colonising the PU surface after 4 weeks. Future studies aim to attempt to further enhance degradation by adding fungi to the compost. In addition, the enzymes secreted and causing degradation of PU will be identified. It is hoped that in the future, waste PU may be diverted for composting rather than disposal via conventional landfill.