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One Man's Trash, Another Baker's Treasure: Scientists Turn Plastic Bottles Into Vanilla Flavoring

Vanilla cupcakes (Getty Images)
Vanilla cupcakes (Getty Images)

You know what they say: One man’s trash is another man’s treasure. Some scientists have taken that phrase to heart.

Stephen Wallace, associate professor at the University of Edinburgh, is part of a group of scientists who are turning plastic bottles into vanillin, an organic compound that serves as the primary component in vanilla extract.

The process begins by depolymerizing the plastic using an enzyme known as polymerase. It’s then fed to a bacterium.

“It simply just eats the plastic waste and uses five different enzymes in the cell to convert the monomer of plastic, which is a molecule that’s called terephthalate acids, into vanillin,” says Wallace.

Despite the revolutionary transformation, Wallace classifies the vanilla as biotechnological vanillin, which is different from synthetic vanillin used in food and cosmetic products.

This vanilla is made petrochemically, using a molecule called phenol, which comes from crude oil, which is also used to make gasoline for cars

The unusual idea to transform plastic in the first place came from new, emerging technology, Wallace said. The tech goes by synthetic biology and it can be used to program common microorganisms to do new things.

Converting a large number of plastic bottles could create a surplus of vanilla, but Wallace says there are a number of uses for it. While adding it into your baking is an obvious choice, it can also be used within cosmetic industries, for pharmaceutical synthesis and even in cleaning products. And the demand is only expected to grow.

“It has at the moment a global demand that’s in excess of 37,000 tons a year,” Wallace says. “And this is expected to almost double in the next, I think, five years or so.”

In regards to how it tastes, Wallace says he doesn’t know. While the researchers have yet to try the vanillin, Wallace says that it does smell nice. It was a great moment for the researchers when they fed the plastic to the bacterium and the smell of vanillin permeated throughout their laboratory.

But the concern many people may have about consuming something that was once plastic is understandable. The road to human consumption is complicated, Wallace says.

“However, our view on this at the moment is if petrochemical vanillin can be improved for human consumption and this comes from fossil fuels and gasoline, etc.,” he says, “I don’t see any reason why using a biotechnological process that’s much greener, much safer, I don’t see any reason why that can be approved as well.”

With the large amount of plastic going to waste and filling up landfills and oceans, Wallace adds that this kind of study can make plastic waste valuable for the economy.

“I think that’s really certainly changed the way that I think about plastic waste. It’s not this problematic end product that we need to deal with, it actually can be used as quite a valuable feedstock for our economy.”


Marcelle Hutchins produced this interview and edited it for broadcast with Jill Ryan. Jeannette Muhammad adapted this interview for the web.

This article was originally published on WBUR.org.

Copyright 2021 NPR. To see more, visit https://www.npr.org.