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takyon [soylentnews.org] writes:

Newly engineered enzyme can break down plastic to raw materials [arstechnica.com]

Plastics have a lot of properties that have made them fixtures of modern societies. They can be molded into any shape we'd like, they're tough yet flexible, and they come in enough variations that we can tune the chemistry to suit different needs. The problem is that they're tough enough that they don't break down on their own, and incinerating them is relatively inefficient. As a result, they've collected in our environment as both bulk plastics and the seemingly omnipresent microplastic waste.

For natural materials, breaking down isn't an issue, as microbes have evolved ways of digesting them to obtain energy or useful chemicals. But many plastics have only been around for decades, and we're just now seeing organisms that have evolved enzymes to digest them. Figuring they could do one better, researchers in France have engineered an enzyme that can efficiently break down one of the most common forms of plastic. The end result of this reaction is a raw material that can be reused directly to make new plastic bottles.

The plastic in question is polyethylene terephthalate, or PET. PET has a variety of uses, including as thin films with very high tensile strength (marketed as mylar). But its most notable use is in plastic drink bottles, which are a major component of environmental plastic waste. PET was first developed in the 1940s, and the first living organism that can break down and use the carbon in PET was described in 2016 [sciencemag.org] [DOI: 10.1126/science.aad6359] [DX [doi.org]]—found in sediment near a plastic recycling facility, naturally.

An engineered PET depolymerase to break down and recycle plastic bottles [nature.com] (DOI: 10.1038/s41586-020-2149-4) (DX [doi.org])

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