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RESEARCHERS at the University of Manchester, UK, have discovered that some types of fungi are capable of digesting polyurethane plastic suggesting it could be composted in future.

Polyurethane is widely-used and difficult to recycle, but a team led by Geoff Robson, a senior lecturer at Manchester’s life sciences faculty, found various species of fungi caused polyurethane pieces mixed into soil to break down faster.

Two techniques, biostimulation and bioaugmentation, were used. Biostimulation essentially involved ‘feeding’ organisms already present in the soil, either with Impranil, a polyurethane dispersion agent which begins the initial break down of the polymer, or with yeast extract. This technique resulted in a 62% increase in degradation compared to untreated soil.

 Bioaugmentation involved cultivating fungi such as Nectria haematococca, Penicillium viridicatum and Penicillium ochrochloron on sterile wheat. These species have been recovered from polyurethane products in previous research. Adding sterile wheat alone to soil containing polyurethane caused an increase in degradation of 28%, but when inoculated with the fungi, this was increased by a further 30–70%. The researchers say this suggests bioaugmentation works together with biostimulation to break down the polymer faster.

 “This is a significant finding. Polyurethanes are used to make many, many products and can take up a large amount of volume in landfill sites, which are rapidly running out of space. This makes it a major environmental pollutant. This study opens the possibility that fungi could be used to degrade these materials instead of dumping them into landfill sites,” says Robson.

He points out that while the fungi are abundant in the environment, polyurethane is known to be susceptible to microbial attack, and most products contain biocides to slow growth of microorganisms.

Robson and his team are now investigating exactly how best to use the fungi to break down polyurethane in waste management.

The research was published in Applied and Environmental Microbiology (doi: 0.1128/AEM.00534-09).