The hungry little bacterium that could hold the key to the world's plastic waste problem

The discovery of a bacterium with the ability to completely break down PET plastic could be a boon for cleaning up plastic waste(Credit: Steven DepoloCC 2.0)

Hundreds of millions of tons of PET (polyethylene terephthalate) plastic are produced each year to package everything from sodas to shampoo. That only a fraction of this is recycled leaves much of it to rest in landfills and the ocean. But efforts to deal with this monumental mess may soon receive a much-needed boost, with scientists in Japan discovering a new bacterium with the ability to completely break down PET plastics in a relatively short space of time.

A team led by Dr Shosuke Yoshida from the Kyoto Institute of Technology unearthed the bacterium, quite literally, by scooping up 250 debris samples from outside a PET recycling plant. Among the soil, sludge and other sediments, they discovered a bacterium that was actually feeding on PET as its energy and carbon source. When it was left alone in a jar with PET plastic, the scientists found that the material was completely broken down within a matter of weeks.

At the heart of this healthy appetite for plastic were a pair of enzymes, which the microbe appears to have evolved in response to its PET-heavy environment. These enable the bacterium, which has been named Ideonella sakaiensis, to reduce the plastic down to its basic building blocks: two environmentally harmless monomers called terephthalic acid and ethylene glycol.

While plastic-eating fungi has been discovered in the past, they haven't been so easy to produce. By identifying the gene behind the bacterium's creation of these two enzymes, the scientists were able to recreate them in the lab and have them break down the plastic on their own, suggesting a more effective approach to recycling and plastic waste management could be on the way.

The research was published in the journal Science.

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