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Scientists identify plastic-chomping bacteria

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A group of German researchers have identified a strain of bacteria capable of breaking down some of the chemical building blocks of polyurethane.

Polyurethane is a flexible, lightweight polymer used in an extremely wide range of products, including cleaning sponges, building insulation, skateboard wheels and footwear. In 2015 alone, polyurethane products accounted for 3.5 million tonnes of plastics produced in Europe.

Unfortunately, polyurethane is also extremely difficult and energy-intensive to recycle or destroy, as thermosetting polymers do not melt when heated. This results in vast quantities of polyurethane being dumped in landfill sites, where they release a cocktail of toxic chemicals (some of which are carcinogenic).

While the UK and many other countries have committed to reducing plastic waste, many researchers are also engaged in efforts to find ways to degrade plastics using microorganisms. This study is among a small handful – most of which focus on fungi – to address the biodegradation of polyurethanes.

The researchers, based at Leipzig’s Helmholtz Centre for Environmental Research-UFZ, identified a strain of bacteria (Psuedomonas sp. TDA1) from a site rich in brittle plastic waste. It belongs to a group of extremophilic bacteria known for their tolerance of toxic organic compounds, such as those released by waste polyurethane. Helpfully, this strain of bacteria is capable of attacking polyurethane bonds.

They performed a genomic analysis to understand how Pseudomonas sp. TDA1 metabolises certain chemical compounds found in polyurethane and found that it is capable of essentially using these compounds to sustain itself.

“The bacteria can use these compounds as a sole source of carbon, nitrogen and energy,” said Dr Hermann Heipieper. “This finding represents an important step in being able to reuse hard-to-recycle [polyurethane] products.”

According to Heipieper, the first step of future research on the bacteria will be to identify the genes that code for the enzymes which break down these compounds, with more basic research required before work can begin exploiting Pseudomonas sp. TDA1’s usual capabilities for polyurethane degradation.

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