Engineered Yeast Turns Plastic Waste Into 3D-Printed Food for Space Missions

A team at Southern Illinois University Carbondale wants you to eat your recycling. They have engineered a consortium of yeasts that breaks down PET plastic bottles and corn stalks into proteins, fats, and flavor compounds, then feeds the resulting slurry into a 3D printer that extrudes it into a vanilla-scented cookie. It sounds like science fiction, but the project is moving out of the lab and toward real food-science testing.

From Water Bottle to Protein Snack

The process starts with polyethylene terephthalate, the same plastic used in disposable water and soda bottles, mixed with agricultural leftovers such as corn stalks and leaves. Heat, high-pressure water, and oxygen shred the mix into carbon-rich fragments. Those fragments become dinner for three engineered yeast strains.

One strain of Saccharomyces cerevisiae turns ferulic acid into vanillin, the compound behind vanilla flavor and aroma. Another, Rhodosporidium toruloides, produces beta-carotene for vitamin A. A third yeast builds protein and fat. The team blends that output with fiber, starch, and sweetener to create an edible paste, then pushes it through a 3D printer fitted with a syringe-style extruder. The result is a small cookie stamped with the Greek letter mu, the signature of the project's Microbites concept.

A NASA Challenge That Kept Going

The idea began as an entry in NASA's Deep Space Food Challenge, the agency's competition to feed astronauts on long-duration missions where fresh resupply is impossible. The SIU team did not win the grand prize; that went to Interstellar Lab and its autonomous greenhouse. NASA still encouraged the group to keep refining the technology, and the researchers presented their latest flavor, aroma, and color improvements at the American Chemical Society Fall 2026 meeting in Chicago.

The space angle is obvious. A crew on a Mars mission cannot pack years of fresh food, and waste plastic has to go somewhere. Turning trash into calories solves two problems with one reactor. But the team is also thinking about Earth. With global food demand projected to rise sharply by 2050, the researchers argue that microbial upcycling could become a way to address both hunger and plastic pollution at once.

The Catch: It Still Costs $60 a Kilogram

There is a long way to go before these cookies show up in a grocery store. The team has not yet won approval for human taste tests, though they report the aroma is promising. Production currently runs about $60 per kilogram, which is far too expensive for routine consumption.

Lead researcher Lahiru Jayakody believes the price can fall as the yeasts become more efficient and the process scales. He may be right, but the bigger hurdle is not biology; it is appetite. Most people will need convincing that food made from old soda bottles is food at all. For now, the Microbites cookie is a clever demonstration that 3D printing and synthetic biology can turn one person's trash into another person's snack, even if that snack is still waiting for its first official bite.