Researchers at Southern Illinois University Carbondale have engineered specialized microbes that transform discarded plastic bottles and agricultural waste into protein-rich, 3D-printed cookies. Developed for NASA’s Deep Space Food Challenge, the edible µBites project offers a potential closed-loop solution for managing plastic waste and sustaining deep-space exploration crews.
While the prospect of eating recycled plastic might initially sound unappetizing, the transformation relies on a rigorous multi-step biological and chemical process. Researchers designed the system to tackle two mounting global pressures simultaneously: the accumulation of plastic pollution in landfills and the growing threat of global food insecurity. According to United Nations data, approximately 2.1 billion people experience food insecurity worldwide, with 645 million facing chronic hunger.
From Discarded PET Plastic and Corn Waste to Liquid Feedstock
The transformation begins with polyethylene terephthalate—commonly known as PET—which is the primary material used for soda bottles, water bottles, and various consumer packaging. The SIU Carbondale team combines this plastic waste with agricultural leftovers, specifically corn stalks and leaves.
To break down these tough materials, researchers utilize a method called oxidative hydrothermal dissolution. This process applies water and oxygen under intense heat and high pressure to strip the durable polymer down into its foundational carbon building blocks. The resulting liquid feedstock forms the base of the food production cycle.
Microbial Engineering and 3D Food Printing
Once the liquid feedstock is ready, it is fed to cultured yeast strains. These programmed microorganisms reassemble the carbon fragments into proteins, fats, and acids, creating nutrient-dense food slurries. To make the mixture palatable, the research team genetically engineered specific yeast strains.
One engineered yeast strain generates an organic compound that provides vanilla scent and flavor directly from plant biomass. Another specialized strain converts ethylene glycol, a molecule found in PET plastic, into beta-carotene—the same pigment that gives carrots their orange color and a precursor that the human body transforms into vitamin A. Once these ingredients combine into raw dough, a 3D food printer extrudes the mixture layer by layer into a consistent cookie shape before a final microwave heating hardens the product.
Safety Testing, Flavor, and Nutritional Analysis
Safety remains a primary focus before any public tasting events can occur. According to the research team, comprehensive laboratory evaluations have already taken place.
“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.”
Lahiru Jayakody, microbiologist at SIU
While human consumption trials are still awaiting final institutional sign-off, preliminary sensory evaluations have already been conducted. Participants in smell tests reported that they would be willing to eat the cookies in resource-limited settings.
Portability for Extreme Earth Environments and Space Missions
The underlying technology was initially conceived as part of NASA’s Deep Space Food Challenge. Because the production unit is tunable and portable, its operational scope extends far beyond traditional food manufacturing plants.
Researcher Lahiru Jayakody noted that the conversion system is particularly well-suited for producing food on-demand in isolated or extreme environments. Potential deployment locations include submarines, disaster relief vehicles, research stations in the Arctic or Antarctic, and eventually Martian or lunar surfaces.
Efficiency Goals and Next Steps for Human Trials
In its current configuration, the conversion system operates on a timeline of a day or two. It is capable of capturing more than 50 percent of the carbon from waste materials and converting it directly into food products.
“With future iterations and R&D efforts, we could recirculate the unconverted carbon to achieve nearly 100 percent conversion.”
Lahiru Jayakody, microbiologist at SIU
While the system is designed around a zero-waste concept, approximately 10 percent of the carbon material may currently escape as waste gas or remain unconverted during processing. Moving forward, the research team is preparing for human trials by conducting simulated digestive studies and working to add starch, fiber, and sweeteners to future iterations of the recipe.
