µBites: Plastic-Derived Cookies From Engineered Yeast

Scientists at Southern Illinois University Carbondale have created a protein-rich cookie called µBites that uses engineered yeast to turn PET plastic and crop residues into food components. The 33-step process takes up to two days and costs about $60 per kilogramme, making commercial production unlikely.

µBites are produced by feeding genetically engineered yeast with carbon-rich compounds derived from PET and agricultural waste. The yeast then converts these compounds into proteins, fats, nutrients and flavoring compounds, which are combined with starch, fiber and sweeteners, extruded through a 3D printer and microwaved.

The project originated from NASA’s Deep Space Food Challenge, which sought technologies that could produce food in long missions where conventional agriculture and resupply are limited. The challenge also supports other innovative projects that can be found in the squad section of the publication.

The research team first developed an oxidative hydrothermal dissolution method that breaks PET and crop residues into carbon-rich compounds that microbes can access. Engineered yeast strains are then fed those compounds and programmed to produce specific food components.

In the latest phase presented at the American Chemical Society’s Fall 2026 meeting, the team engineered baker’s yeast, Saccharomyces cerevisiae, to produce vanilla-flavored vanillin from plant-derived ferulic acid, while a strain of Rhodosporidium toruloides used ethylene glycol derived from PET to produce beta-carotene, a precursor to vitamin A.

The resulting mixture was extruded through a 3D printer and cooked in a microwave. The system remains far from commercial viability, with 33 steps, a 1-to-2 day production time and a cost of $60 per kilogramme.

While the food industry works to keep microplastics out of products, µBites asks consumers to embrace plastic waste as a starting point for a snack. The system is designed to dismantle PET and feed its carbon-rich components to microbes, which then construct new biological molecules.

The principle is that PET should disappear during processing, leaving proteins, fats, vitamins and flavor compounds rather than plastic particles. However, consumers associate plastic with pollution and chemical migration, making it difficult to convince them that intentionally eating protein made from plastic-derived carbon is safe.

Safety evidence will determine whether µBites remain a provocative experiment or become a legitimate ingredient platform. The researchers have conducted internal and third-party laboratory analyses for toxic chemicals, heavy metals, allergens and food pathogens. Simulated digestion studies and further testing are also underway before human trials.

Blind sensory assessments reportedly found the aroma appealing and the texture pleasant to touch, while the product smells like a real cookie. However, smell and texture cannot establish safety, digestibility or nutritional value. The latest findings were presented as a conference poster rather than a completed human safety study, so considerable testing remains before the cookies can be considered ready for consumers.

Regulators would need evidence covering purity, nutritional composition, toxicology, allergenicity and process consistency before any bakery or snack manufacturer could contemplate using the ingredients. Consumer acceptance presents another obstacle because the proposition combines several technologies that already generate suspicion: genetically engineered microorganisms, precision fermentation, 3D-printed food and intensive processing.

The SIU Carbondale system currently converts more than 50% of the carbon in its waste feedstock into food. Researchers hope to recirculate the remainder and eventually approach 100% conversion, although around 10% could still be released as gas or remain unused.

Even dramatic efficiency gains would not make µBites a realistic solution to the plastic crisis. More than 400 million tonnes of plastic waste are generated annually, and no plausible market for cookies, milk alternatives, meat substitutes or animal feed could consume it all.

Professor Jason Hallett of Imperial College London told New Scientist that “You’re not going to turn it all into cookies. It’s not a solution to the plastic-waste crisis. There’s no way you could do this commercially. We’re not gonna be eating plastic cookies.”

The concept becomes more credible in extreme environments for which it was developed. Spacecraft, submarines, polar research stations and disaster-response operations all face constraints around storage, resupply and waste disposal. A portable system capable of turning carefully controlled waste streams into protein, vitamins and flavorings could provide an emergency or supplementary food source.

Cookies are only the proof of concept. The researchers plan to explore other food products that could be produced from plastic waste, but the current focus remains on the µBites cookie.

The latest findings were presented in the stats section of the publication, indicating that the process is still experimental and requires extensive safety and regulatory testing before any commercial use.