Would you eat a cookie that was made from plastic?
Technically, we're all ingesting an ungodly amount of plastic already, in the form of micro- and nanoscopic particles in our food.
But now, researchers from Southern Illinois University (SIU) Carbondale are trying to get us to eat the stuff on purpose.
It takes the form of cookies they call µBites, which, if you know your scientific notation symbols, is pronounced "microbites".
They may sound even less appetizing than all the bugs we might have to eat in the future, but these cookies have undergone a whole lot of processing to make them (theoretically) safe to eat, nutritious, and hopefully tasty.
The research started as part of NASA's Deep Space Food Challenge, and the team has just presented it at a symposium organized by the American Chemical Society.
"Converting (biodegradable) food-grade plastic into food is feasible," Lahiru Jayakody, microbiologist at SIU, told ScienceAlert.
"The µBites system is a tunable and portable device that integrates all necessary components… These units could be deployed in submarines or disaster relief vehicles to produce on-demand, on-site food.
"The process is particularly suited for using carbon waste in extreme environments such as deserts, the Arctic, or the Antarctic to make food – and yes, potentially one day on Mars or the lunar surface."
Plastic is one of the most ubiquitous materials in the modern world, thanks to its flexibility and durability. But that pro becomes a con when it's time to dispose of it, and most plastic products end up in landfill, even if they are recyclable.
Recent research has found some success with turning plastic waste into various useful things – not just other plastic products, but materials, fuels, even medicines. And soon, we might be able to add 'food' to that list.
There are obviously a few steps between a discarded plastic bottle and an edible cookie.
The first is a process developed at SIU called oxidative hydrothermal dissolution – basically, using oxygen and water, under intense heat and high pressure, to break materials down into their carbon building blocks.
In this case, the team used this process on polyethylene terephthalate (PET) plastic, along with agricultural waste like corn stalks and leaves, to produce a liquid feedstock.
This stuff is then fed to cultured yeast, which converts it into "nutritious food slurries".
And bam – there's your cookie dough starter.
That end result might technically be edible, but would probably have a flavor and nutritional profile little better than cardboard.
So, the researchers engineered different strains of yeast to turn various feedstocks into other food ingredients, including proteins, lipids, vitamins, aromas, colorings, and flavorings.
For example, one strain of yeast was engineered to produce an organic compound called vanillin, which, as the name suggests, provides a vanilla scent and flavor.
Another was designed to make a pigment called beta-carotene, which gives carrots their orange coloring and which our bodies turn into vitamin A.
These ingredients are combined into a raw dough, which is loaded into a 3D food printer and piped out layer by layer, in a consistent shape.
Finally, the cookie is cooked in a microwave to harden it into the familiar foodstuff.
We asked the team the question that's surely on everyone's lips: 'Well, how does it taste?'
Unfortunately, no one has been allowed to try one yet – it's probably better to wait until the safety tests are completed. Blind sensory tests, however, suggest it smells nice and has a pleasing texture to the touch.
"We have comprehensively analyzed the food products we created in the lab, as well as through accredited third-party laboratories, to ensure µBites cookies are free from toxic chemicals, heavy metals, allergens, and food pathogens," Jayakody told ScienceAlert.
"We are conducting simulated digestive studies and other necessary analyses in preparation for human trials."
Taste tests pending, there's still plenty of other work to do before people in remote areas, disaster zones, or space are regularly chowing down on µBites.
In its current form, the system takes a day or two and can convert more than 50 percent of the carbon from waste materials into food products, but the team plans to improve that.
"With future iterations and R&D efforts, we could recirculate the unconverted carbon to achieve nearly 100 percent conversion," said Jayakody.
"The system is designed to achieve a zero-waste concept; however, approximately 10 percent of the carbon material may be released as waste gas or remain unconverted throughout the process."
While the process may sound technical – it currently involves 33 steps – the equipment can be self-contained and portable enough for use in situations where space and resources are limited.
That said, the team says a major hurdle is how to get it working in microgravity. But in the meantime, there are plenty of use cases here on Earth.
Related: Scientists Figured Out How to Turn Plastic Waste Into a Parkinson's Drug
And it doesn't have to be limited to cookies, either.
"We made cookies as a proof of concept, but the food ingredients can also be used to produce other food items that require protein, aroma, and vitamins, such as milk alternatives and meat alternatives," Jayakody said.
"Additionally, we are exploring the use of µBites in feed manufacturing."
The researchers presented their work on Monday at the fall meeting of the American Chemical Society in Chicago. You can also read about their work in an industry highlight published in Trends in Biotechnology.
This article was fact-checked by Clare Watson and edited by Clare Watson. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.