This plastic-gobbling enzyme just got an upgrade

Scientists’ tweak led to more breakdown of plastics found in polyester and plastic bottles

pile of plastic trash

TRASH STASH  Scientists have modified a bacterial enzyme to make it even better at breaking down PET, a plastic widely used in disposable water bottles.

Bo Eide/Flickr

Just a few tweaks to a bacterial enzyme make it a lean, mean plastic-destroying machine.

One type of plastic, polyethylene terephthalate, or PET, is widely used in polyester clothing and disposable bottles and is notoriously persistent in landfills. In 2016, Japanese scientists identified a new species of bacteria, Ideonella sakaiensis, which has a specialized enzyme that can naturally break down PET.

Now, an international team of researchers studying the enzyme’s structure has created a variant that’s even more efficient at gobbling plastic, the team reports April 17 in Proceedings of the National Academy of Sciences.

The scientists used a technique called X-ray crystallography to examine the enzyme’s structure for clues to its plastic-killing abilities. Then, they genetically tweaked the enzyme to create small variations in the structure, and tested those versions for PET-degrading performance. Some changes made the enzyme work even better. Both the original version and the mutated versions could break down both PET and another, newer bio-based plastic called PEF, short for polyethylene-2,5-furandicarboxylate. With a little more engineering, these enzymes could someday feast at landfills.

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