NASA-backed research makes 3D printed cookie out of plastic waste

You’ve heard of 3D printed parts made from plastic waste, and you’ve heard of 3D printed food, but have you heard of 3D printed food made from plastic waste? Neither had we before today. Researchers from Southern Illinois University (SIU) Carbondale have developed a way to turn PET plastic waste into edible cookies using microbes and 3D printing. The research project is funded in part by NASA’s Deep Space Food Challenge, which is looking for innovative food production methods that can ensure astronauts are well fed on long missions while using minimal resources.

For the SIU Carbondale research team, turning to plastic waste as a resource for nutrients seemed like a natural choice. As Associate Professor Lahiru Jayakody explained: “We were trying to develop technologies for plastic upcycling to make more valuable products. We thought, why not focus on making food? Because plastic is carbon and food is carbon.”

PET, or polyethylene terephthalate, is one of the most commonly consumed types of plastic and generates a ton of waste every day in the form of water bottles and food packaging. The plastic material also contains molecules with carbon, which the researchers believed could be rebuilt into edible proteins. To achieve this transformation, the team turned to microbes, such as yeast, to do the work.

According to the SIU team, they programmed a number of yeast varieties, including baker’s yeast, to convert the carbon molecules in the plastic—as well as other types of waste, like agricultural waste—into proteins, vitamins, and even flavorings. “Microbes are very clever. So, we are using their traits to solve the problems we created,” added Jayakody.

In more technical terms, the researchers used a process called oxidative hydrothermal dissolution—itself developed at SIU by geology professor Ken Anderson—which uses water and oxygen, both at a high temperature and under pressure, to break down PET waste and corn plant stalks into pieces that could be more easily digested by the yeast microbes. These pieces were then fed to the programmed yeasts, which successfully converted the waste into different edible ingredients. These ingredients were then mixed with fiber, starch, and sweetener, creating a 3D printable paste.

The resulting edible is a 3D printed cookie, high in protein, that the researchers have called a “µBite”, or microbite. To date, no one has actually tried one of the cookies because the team is waiting on “institutional approval” to carry out the first taste tests. Based on available data and smell tests, however, the cookies seem promising, and several people said they would be willing to eat them if resources were limited, like on deep-space missions or in disaster stricken zones where food is not readily available.

The research team is also interested in making the µBites more appealing to general consumers by creating a variety of food additives using the programmed yeasts. To date, the team has used baker’s yeast to turn plant biomass into vanilla flavoring and has used another type of yeast to convert ethylene glycol in PET into a plant pigment called beta-carotene that the body can turn into vitamin A. There also seems to be potential for additional variations. “We’re using microbes to develop the cookie into a more attractive, consumer-friendly product,” said graduate student Sandhy Jayasekara. Down the line, the team believes it will even be able to make the added ingredients to the cookies (i.e. the starch, fiber, and sweetener) using microbes.

Whether or not you think you’d eat one of the 3D printed cookies alongside a cup of tea, the NASA-funded work could be highly impactful. If plastic waste becomes a source of nutrients for humans, it could be possible to provide food in places where natural resources are scarce, like on the moon or on Mars. Even here on Earth, the SIU team believes its 3D printed cookies could have important applications, like feeding crews on submarines or in areas where hunger is endemic. “Global food demand is expected to rise 35–56% by the year 2050, and about 30% of the world population will be at risk of hunger in the future,” Jayakody concluded. “The way to address that, I believe, is by using microbes.”