Researchers at Southern Illinois University Carbondale say they have engineered yeast to turn compounds from PET plastic and agricultural waste into proteins, fats, vitamins, and flavorings, then used those ingredients to 3D-print protein-rich cookies called µBites, pronounced microbites. The team presented the work at the American Chemical Society's fall meeting at McCormick Place in Chicago, according to the society's release.

The first question most readers will ask is whether anyone is eating plastic. The answer is no. The waste is broken down into smaller molecules, the yeast consumes those molecules, and the yeast builds food compounds from them. The plastic itself is not an ingredient.

Whether the cookies are ready to eat is a separate question. The researchers say available data indicate µBites are safe to eat, but formal taste tests are still waiting on institutional approval. So far, participants have judged the cookies only by their aroma, and most said they would be willing to eat them in situations where food was scarce.

How a Soda Bottle Becomes Cookie Protein

The process starts with oxidative hydrothermal dissolution, a proprietary technique developed by SIU Carbondale geology professor Ken Anderson. It combines water and oxygen under high temperature and pressure to break resistant materials into compounds microbes can use. Inputs include polyethylene terephthalate, the plastic in many soda and water bottles, along with discarded corn stalks and leaves and other plant material.

Associate Professor Lahiru Jayakody and graduate student Sandhya Jayasekara then programmed several types of yeast, including ordinary baker's yeast, to convert the resulting molecules into proteins, fats and acids. One engineered baker's yeast strain makes vanilla flavoring from plant biomass. Another strain uses ethylene glycol derived from PET to produce beta carotene, which the human body can convert into vitamin A.

The yeast-made ingredients are blended with fiber, starch and sweetener and pushed through a 3D printer. The project grew out of plastic upcycling research. "We thought, why not focus on making food? Because plastic is carbon and food is carbon," Jayakody said. The approach builds on a well-established practice, since engineered microbes are already used to make substances such as insulin.

Why Space Agencies Care About Recycled Calories

The work traces back to NASA's Deep Space Food Challenge, a competition that ran from 2021 to 2024 in coordination with the Canadian Space Agency. It sought food production technologies that require minimal resources and produce minimal waste while providing safe, nutritious and tasty food for long missions, where astronauts cannot depend on regular shipments from Earth.

NASA also framed the challenge as useful on the ground, particularly in extreme environments, resource-scarce regions and places where disasters disrupt critical infrastructure. The SIU team lists submarines, disaster areas and future settlements on the moon or Mars as possible uses.

The challenge concluded in 2024, when NASA awarded $1.25 million to three U.S. teams in its final round. The society's release does not say how the SIU team placed in the competition.

Readers should also know who paid for the work. According to the release, the research was funded by the NASA Deep Space Food Challenge and a National Science Foundation Faculty Early Career Development Program grant.

A Promising Lab Demonstration, Not a Grocery Product

The evidence is early. The results were presented at a scientific conference and described in a society press release, which does not cite a peer-reviewed paper. No formal human taste trials have taken place, and nothing in the release indicates the cookies have been reviewed for commercial sale.

Jayakody said he hopes the cookies could be ready for public consumption within the next few years, and he cited projections that global food demand could rise 35 to 56 percent by 2050. Those are his statements rather than findings of this research, and any timeline depends on safety testing and approvals that have not yet happened.

Several questions are not addressed in the public materials, including how the process screens for leftover plastic-derived chemicals, how much protein and other nutrients a serving provides and how much energy the high-pressure breakdown step consumes. Published data and independent testing would be needed to answer them before the cookies could be considered for wider use.

The team is still working to make the cookies more appealing to people who have other food choices, and to have microbes produce the starch, fiber, and sweetener that are currently added separately.

Plastic Waste Remains a Present-Day Problem

The technology does not change today's plastic picture. The EPA reports that the U.S. generated 35.7 million tons of plastic in 2018, the latest year in its plastics data table, and recycled 8.7 percent of it overall. PET bottles and jars fared better, with a 29.1 percent recycling rate, while landfills received 27 million tons of plastic that year.

Nature World News has covered other biological approaches to plastic, including a plastic-eating fungus discovered in the Amazon, and those also remain far from large-scale use. For households, practical steps have not changed: check local recycling rules for PET bottles, keep recyclables clean, and cut single-use plastic where possible. No one should attempt to process or eat plastic at home.

The next milestones to watch are approval for formal taste testing and a peer-reviewed publication with full safety data. Until then, µBites remain a proof of concept, a clever route from waste to nutrition that has not yet reached anyone's plate.

What Readers Want to Know

Are people eating plastic in these cookies? No. The plastic is broken down, engineered yeast converts the resulting molecules into food compounds, and those compounds go into the cookies.

Are the cookies safe to eat? The researchers say available data indicate they are, but formal taste tests await institutional approval and the findings have not been published in a peer-reviewed journal.

Can I buy µBites? No. They are a research prototype and are not sold to the public.

Why is NASA connected to the project? The work was funded partly through NASA's Deep Space Food Challenge, which sought low-waste food systems for long space missions.

Will this fix plastic pollution? Not in the near term. EPA data show most U.S. plastic waste is landfilled, and this process remains at the laboratory stage.