Tasty Trash? Scientists Make Vanilla Flavoring from Used Plastic

Whether you consume it in ice cream, coffee, cupcakes, pudding, or protein shakes, the vanilla you eat in the future might taste just a little bit sweeter thanks to a surprising new ingredient: used plastic.

Admittedly, it doesn’t sound very appetizing. To scientists at Scotland’s University of Edinburgh, however, what’s even less palatable is plastic waste, which currently enters the ocean at a rate of 8 million tons per year—enough that plastic waste will outweigh all of the ocean’s fish by the year 2050, according to Conservation International. To help stem the tides of plastic pollution on land and at sea, they’ve devised a novel way to turn it into vanillin, a chemical compound in vanilla extract that gives it its distinct vanilla aroma and flavor.

Although it can be found in natural vanilla bean extract, vanillin also can be made synthetically using chemicals derived from petroleum. To create it from plastic, instead, researchers genetically modified a strain of E. coli bacteria so that it can make vanillin from terephthalic acid (TA)—a raw material used in the production of plastic bottles, which can be broken down using special enzymes that reduce them to their basic chemical components. Because it uses microbial fermentation, the chemistry is similar to that of brewing beer.

“The global plastic waste crisis is now recognized as one of the most pressing environmental issues facing our planet, prompting urgent calls for new technologies to enable a circular plastics economy,” scientists Joanna Sadler and Stephen Wallace state in their research, which was published this month in the journal Green Chemistry. Their work, they say, “demonstrates the first biological upcycling of post-consumer plastic waste into vanillin using an engineered microorganism.”

“This is the first example of using a biological system to upcycle plastic waste into a valuable industrial chemical and it has very exciting implications for the circular economy,” Sadler told British newspaper The Guardian.

According to the paper, approximately 85% of the world’s vanillin is synthesized from chemicals that are derived from fossil fuels, including crude oil. That’s because demand for vanillin—which is used widely not only in food, but also in cosmetics, pharmaceuticals, cleaning products, and herbicides—far outstrips supply. In Madagascar, which grows 80% of the world’s natural vanilla, pollinating, harvesting, and curing vanilla beans is a tedious and painstaking process that couldn’t possibly yield enough vanillin for modern appetites. And even if it could, the only way to naturally increase vanillin supply would be to plant more vanilla plantations, which would drive deforestation.

Being able to create vanillin with plastic instead of petroleum means increasing vanillin supply while mitigating plastic waste, reducing industrial reliance on fossil fuels, and preserving forests.

“This is a really interesting use of microbial science to improve sustainability,” Ellis Crawford, publishing editor at the United Kingdom’s Royal Society of Chemistry, told The Guardian. “Using microbes to turn waste plastics, which are harmful to the environment, into an important commodity is a beautiful demonstration of green chemistry.”

During their experiments, researchers successfully converted 79% of the TA in recycled plastic into vanillin. With additional engineering, Sadler and Wallace believe they can further increase that conversion rate and perhaps even produce other chemicals, like compounds used in perfumes.

“Our work challenges the perception of plastic being a problematic waste and instead demonstrates its use as a new carbon resource from which high-value products can be made,” Wallace told The Guardian.

The University of Edinburgh is just the latest to explore alternative, sustainable sources of vanillin. For example, Norwegian company Borregaard has been making and selling vanillin derived from wood—spruce trees, for example—since 1962. In 2009, it published an independent analysis showing that greenhouse gas emissions from making wood-based vanillin in its “biorefinery” are 90% lower than greenhouse gas emissions from making petroleum-based vanillin.

“Since nature will not be able to supply the markets with … enough vanilla, we need alternatives that might even be better in terms of sustainability,” Thomas Mardewel, then business director of aroma chemicals at Borregaard, told FoodNavigator.com in a 2009 interview.