Bacteria found to eat PET plastics could help do the recycling 

In 2013, 56 million tons of PET were manufactured – about a quarter of all plastics produced that year – but only 2.2 million tons were recycled, the team says.

Nature has beaten us to it again. It has taken just 70 years for evolution to throw up a bacterium capable of breaking down and consuming PET, one of the world’s most problematic plastic pollutants.

Japanese researchers discovered and named the species, Ideonella sakaiensis, by analysing microbes living on debris of PET (polyethylene terephthalate) plastics they collected from soil and wastewater.

The bacterium seems to feed exclusively on PET and breaks it down using just two enzymes.

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It must have evolved in just 70 years the capability to do this because the plastics were only invented in the 1940s.

The team hopes the discovery will lead to new ways of breaking down plastic, using either the bacteria themselves, or the two enzymes they use for the job.

So how do the bacteria do it?

They link to the PET with tendril-like threads. They then use two enzymes sequentially to break down PET into terephthalic acid and ethylene glycol, the two substances from which it is manufactured and that are not harmful to the environment.

The bacteria then digest both substances. This could mean they would be useful for getting rid of polluting plastics in the environment.

 Their ability to reconstitute the starting materials also lends them to recycling strategies. But the process takes a long time – about 6 weeks at 30°C to fully degrade a thumb-nail-sized piece of PET.

“We have to improve the bacterium to make it more powerful, and genetic engineering might be applicable here,” says Oda, whose team is already experimenting with this.

One way of speeding things up would be to transfer the genes that make the two enzymes into a faster growing bacterium like Escherichia coli, says Uwe Bornscheuer of Greifswald University in Germany.

Journal reference: Science, DOI: 10.1126/science.aad6359

About Stan Flouride

THIS BLOG IS ALWAYS AD-FREE I make stuff and do things.
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