Scientists at Southern Illinois University Carbondale have developed a technique that turns plastic waste and agricultural byproducts into a mixture that can be 3D-printed into cookies. The project aims to explore new ways of using materials that normally end up as trash.
The team used genetically modified yeasts to break down components of plastic and leftover crop material, such as discarded plant stems. These microorganisms can transform the materials into proteins, fats, acids and compounds used to add flavor.
A modified yeast breaks down the waste
The researchers worked specifically with polyethylene terephthalate, or PET, a plastic widely used in water bottles, food packaging and clothing. Before the yeast can use it, the PET must go through a process called oxidative hydrothermal dissolution, which uses heat, water and oxygen to break the plastic into fragments small enough for the microorganisms to process.
The resulting products are then combined with fiber, starch and sweetener. One of the yeast strains used also managed to produce a vanilla flavoring from plant biomass.
The finished mixture was fed into a 3D printer to make cookies in various shapes. The team chose the Greek letter mu as its design and named the products "muBites," a reference to microbites.
Lahiru Jayakody, a microbiologist at Southern Illinois University and the researcher leading the project, said she thought the cookies had a pleasant, appealing aroma and would also taste good. She said the team had not yet tasted them but that they smelled good, like a real cookie.
The project still faces major limitations
Although the researchers believe the cookies could be safe and pleasant to eat, they have not yet tasted the muBites. The team is waiting for approval from the university before consuming products made through this process.
The research was presented at a meeting of the American Chemical Society in Chicago and received funding from NASA's Deep Space Food Challenge program. Because of that, one of its potential applications would not necessarily be everyday eating, but future long-duration space missions.
The idea is that the technology could allow different waste materials to be used to produce food during long journeys to places such as Mars. However, the method is still too expensive to become a conventional food alternative, with producing one kilogram of the cookies costing around 60 dollars.
Not a solution to the plastic crisis
Some specialists say the technique cannot solve the global plastic waste crisis on its own. Jason Hallett, of Imperial College London, told New Scientist that the world produces 400 million tons of plastic waste a year, and that not all of it can be turned into cookies. He said the technique was not a solution to the plastic waste crisis, that it was impossible for it to be commercially viable, and that people were not going to eat plastic cookies.
For now, the muBites represent more of a demonstration of how biotechnology and 3D printing could be combined to turn waste materials into usable resources. Their most promising application could be in settings where transporting large amounts of food is especially difficult, such as future space missions.
