Scientists turn plastic and corn waste into protein-rich edible cookies using programmed yeast
A cookie made partly from soda bottles and corn stalks might sound unappetizing, but researchers say the real product is protein, not plastic. Scientists at Southern Illinois University Carbondale have programmed yeast to convert plastic and agricultural waste into edible proteins, vitamins, and flavor compounds. The team baked the result into a snack they call µBites.
The project was developed as part of NASA-backed research aimed at producing food in resource-limited environments, including deep-space missions. Associate professor Lahiru Jayakody led the work alongside graduate student Sandhya Jayasekara. Jayakody said the underlying logic was straightforward: plastic and food are both, at their core, forms of carbon.
Turning bottles into bites
The team targeted polyethylene terephthalate, or PET, the plastic used in most soda and water bottles. PET is carbon-rich, and Jayakody's team reasoned that carbon-based plastic waste could theoretically be rebuilt into carbon-based food.
Similar rebuilding could technically be achieved through industrial chemical reactions and solvents, but the researchers instead outsourced the work to microbes as a simpler, more eco-friendly alternative . Programmed yeast strains, including ordinary baker's yeast, converted molecules pulled from PET and discarded corn stalks and leaves into proteins, fats, and acids.
A high-pressure head start
Before the yeast gets involved, the raw plastic and plant waste passes through a process called oxidative hydrothermal dissolution. SIU Carbondale geology professor Ken Anderson developed the method. It uses water and oxygen at high temperature and pressure to break tough material down into fragments small enough for microbes to consume.
Once broken down, those fragments are fed to the programmed yeast , which reassembles them into new food ingredients. Researchers then mixed in fiber, starch, and sweetener before extruding the blend through a 3D printer to form the finished cookies.
Safe, but untasted
Data collected so far indicate the cookies are safe to eat, according to the researchers. Formal taste testing has not yet begun, however, while the team awaits institutional approval. In the meantime, informal aroma testing has drawn positive reactions, with participants indicating they would be willing to eat the cookies if food options were limited.
Jayasekara has also engineered yeast strains capable of producing more conventional food additives, aiming to make the product more appealing outside of emergency use. One strain now produces vanilla flavoring from plant biomass, while another converts ethylene glycol from PET into beta-carotene, a compound the body converts into vitamin A.
Beyond the cookie
Researchers eventually want to produce every ingredient in µBites, including the added starch, fiber, and sweetener, using microbes rather than conventional sourcing. Jayakody said he expects the product could reach public availability within a few years, with potential uses ranging from submarines to lunar or Martian outposts.
Jayakody pointed to United Nations projections showing global food demand could rise 35 to 56 percent by 2050. Roughly 30 percent of the world's population could be at risk of hunger by then. He argued that microbial food production offers one practical path toward addressing that gap.
Note: This research was presented at a meeting of the American Chemical Society. ACS does not conduct research.
