Scientists accidentally create plastic-eating mutant enzyme

plastic pollution
via Greenpeace

These mutant enzymes with a taste for waste could lead to the full recycling of single-use bottles.

In general, one doesn’t want scientists in a lab to accidentally create mutant things with appetites. But if that hunger happens to be for the plastic used to make single-use bottles – something that doesn't generally degrade in nature and is basically the scourge of modern humanity – I’d say break out the champagne and cigars.

The scientists in just such a scenario comprise an international team that was working off of a 2016 discovery of the first bacterium that had naturally evolved to eat plastic. In studying the plastic-eating enzyme that the bacterium produced, they were looking at how the enzyme evolved – in the process, a tweak to the enzyme revealed that they had inadvertently made it even better at breaking down the bottle plastic, PET (polyethylene terephthalate).

“What actually turned out was we improved the enzyme, which was a bit of a shock,” says lead researcher, John McGeehan from the University of Portsmouth, UK. “It’s great and a real finding.”

Currently, we buy around 1,000,000 plastic bottles each minute around the world. (Let that sink in for just a second.) We recycle a measly 14 percent of that, much of the rest ending up in the ocean, which is slowly becoming a giant pot of animal-killing plastic soup. And the problem with the recycled plastic is that it can only be turned into fiber that is used in other applications; think carpeting, fleece and tote bags.

With the new enzyme, however, the idea is it that it can be put to use to turn old plastic into new plastic.

“What we are hoping to do is use this enzyme to turn this plastic back into its original components, so we can literally recycle it back to plastic,” says McGeehan. “It means we won’t need to dig up any more oil and, fundamentally, it should reduce the amount of plastic in the environment.”

“You are always up against the fact that oil is cheap, so virgin PET is cheap,” he continues. “It is so easy for manufacturers to generate more of that stuff, rather than even try to recycle. But I believe there is a public driver here: perception is changing so much that companies are starting to look at how they can properly recycle these.”

Now back to the horror film premise of unleashing mutants into the environment ... one can’t help but ask, isn't there potential for things to run amok?

Oliver Jones, a chemist from RMIT University in Melbourne, Australia, tells The Guardian, “Enzymes are non-toxic, biodegradable and can be produced in large amounts by microorganisms. There is still a way to go before you could recycle large amounts of plastic with enzymes, and reducing the amount of plastic produced in the first place might, perhaps, be preferable. [But] this is certainly a step in a positive direction.”

Even so, other experts say a full life-cycle assessment would be required to ensure that solving the plastic problem in this way wouldn’t lead to other problems, like additional greenhouse gas emissions. And obviously, reducing the production and use of single-use plastics in the first place can’t be emphasized enough.

But in the meantime, if we can get some these enzymes working on the task, safely reducing the amount of virgin PET being produced certainly couldn’t hurt ... saving the world, one accidental mutant lab creation at a time.

The research was published in the journal Proceedings of the National Academy of Sciences; and you can read much more about it in The Guardian.

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