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Planet Earth

Scientists Accidentally Make Super-Efficient Plastic-Eating Enzyme


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In 2016, scientists discovered a bacterium that had evolved to eat plastic. Now, they’ve unlocked the structure of a critical enzyme that it produces.

Whereas oceans take centuries to break down PET (polyethylene terephthalate) plastic used in soft drink bottles, this mutant enzyme takes only a few hours to accomplish the same task—and scientists think they’re inadvertently made the process more efficient in the lab. Their finding could pave the way toward solutions to global pollution problems that plague our seas and suffocate wildlife.

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Plastic bottles caught in a fishing net

Here’s Damian Carrington, reporting for the Guardian:

The new research, published in the journal Proceedings of the National Academy of Sciences, began by determining the precise structure of the enzyme produced by the Japanese bug. The team used the Diamond Light Source, near Oxford, UK, an intense beam of X-rays that is 10 billion times brighter than the sun and can reveal individual atoms.

The structure of the enzyme looked very similar to one evolved by many bacteria to break down cutin, a natural polymer used as a protective coating by plants. But when the team manipulated the enzyme to explore this connection, they accidentally improved its ability to eat PET.

“It is a modest improvement—20% better—but that is not the point,” said McGeehan. “It’s incredible because it tells us that the enzyme is not yet optimized. It gives us scope to use all the technology used in other enzyme development for years and years and make a super-fast enzyme.”

One approach to using this enzyme could be to transplant it into an “ extremophile ” bacteria that can survive temperatures above 158° F, the point at which PET undergoes a phase change—making it easier to degrade. Regardless, if plastic-destroying enzymes can be produced en masse and sprayed on huge oceanic garbage patches , we’ll be one step closer to solving the world’s pollution crisis.