Microbes Turn PET Waste Into 3D Printed Food
Researchers at Southern Illinois University (SIU) Carbondale have developed a process that uses engineered yeasts to convert plastic and agricultural waste into edible ingredients. The team used these ingredients to produce protein-rich, 3D-printed cookies called µBites, pronounced ‘microbites’.
The research explores a new form of biological upcycling that could help address both plastic pollution and food security. It forms part of a NASA-led project focused on food production in resource-limited environments, including long-duration space missions.
Plastic As A Carbon Source
The process uses polyethylene terephthalate (PET), a widely used plastic found in water and soft-drink bottles. As PET contains carbon-rich molecules, the researchers investigated whether microorganisms could transform these compounds into nutrients.
They combined PET with discarded maize stalks and leaves, as well as other forms of biomass. The mixture underwent oxidative hydrothermal dissolution, a proprietary process developed by SIU Carbondale geology professor Ken Anderson. Using water and oxygen at high temperatures and pressures, the method breaks down resistant waste materials into smaller components that microbes can access.
The researchers then fed these components to engineered yeasts, including baker’s yeast. The microorganisms converted them into food ingredients such as proteins, fats and acids. Fibre, starch and sweetener were added before the mixture was extruded through a 3D printer to form the cookies.
Engineering Flavour And Nutrition
Graduate researcher Sandhya Jayasekara also modified yeast strains to produce additional nutrients and flavourings. One strain of baker’s yeast can generate vanilla flavouring from plant biomass. Another converts ethylene glycol derived from PET into beta-carotene, which the human body can turn into vitamin A.
According to the researchers, available data indicate that the µBites are safe to eat. However, the team is still awaiting institutional approval to conduct taste tests. Initial aroma assessments were positive, and most participants indicated that they would consider eating the product in situations where conventional food supplies were limited.
Food Production In Extreme Environments
The researchers aim to produce more of the cookies’ ingredients, including their starch, fibre and sweetener, through microbial processes. They hope the technology could eventually support food production in disaster zones, submarines and remote locations, as well as future settlements on the Moon or Mars.
Although the research remains at an experimental stage, it demonstrates how engineered microorganisms, waste-processing technology and additive manufacturing could combine to create new circular production systems. Further safety testing, approval and development will be required before foods made from plastic-derived compounds can become available for public consumption.
The research received funding from the NASA Deep Space Food Challenge and a US National Science Foundation CAREER grant.
Source: American Chemical Society (ACS)
Photo: SIU