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The announcement was made by an agency within the U.S. Department of Defense in 2019. phone The research project was aimed at helping the military deal with the massive amounts of plastic waste generated when they deploy to remote or disaster-stricken areas. The service wanted a system that could convert things like food wrappers and water bottles into usable products like fuel and food. The system had to be small enough to fit inside a Humvee and require little energy to operate. It also had to be powered by microbes that eat plastic.
“When we started this project four years ago, the idea was there, and it made sense in theory,” says Michigan Technological University microbiologist Steven Tegtman, who leads one of the three funded research groups. But initially, he says, “this effort felt more like science fiction than something that would actually work.”
That uncertainty was key. The Defense Advanced Research Projects Agency (DARPA) supports high-risk, high-reward projects, which means there’s a good chance that any individual effort will fail. But if the project succeeds, it could represent a true scientific breakthrough. “Our goal is to move from disbelief: ‘You’ve got to be kidding me. What do you want to do?’ to ‘Actually, that might be possible,'” says Leonard Tender, a DARPA program manager overseeing the plastic-waste project.
The problems with plastic production and waste are well known. According to the United Nations Environment Programme, the world is home to approximately 440 million tonnes The amount of plastic waste is increasing every year. Landfill Or in the sea Microplastics, Plastic pelletsand Plastic bags Many governments and experts believe that the solution to this problem is Reduce production, and some countries and US states have introduced additional policy To promote recycling.
For many years, scientist Also, Experiment and Various species of Plastic-eating bacteriaBut DARPA is taking a slightly different approach, exploring compact, portable solutions to using plastic to make something entirely different: human food.
Tectman quickly added: “The goal is do not have The hope is that the plastic won’t be fed to humans, but that the plastic-eating microbes in his body will themselves prove suitable for human consumption. Tectman thinks the bulk of the project can be completed in a year or two, but the food phase could take longer. His team is currently conducting toxicity tests, after which they’ll submit their results to the Food and Drug Administration for review. Even if that all goes well, more challenges lie ahead. “There’s an element of discomfort that I think we’ll have to overcome,” Tectman said.
The military isn’t the only team working to turn microbes into nutrients: From South Korea to Finland, a handful of researchers and companies are investigating whether microbes could help feed a growing global population in the future.
Kill two birds with one stone
According to Tender, DARPA’s call for proposals aimed to solve two problems at once. First, the agency wanted to reduce what it called supply chain vulnerabilities. During wartime, the military needs to transport supplies to troops in remote locations, threatening the safety of those aboard the vehicles. Additionally, the agency wanted to reduce the vulnerability of the supply chain. Dangerous Incineration Pits “Responsibly removing these waste materials from the site is a big step forward,” Tender said.
Michigan Tech’s system starts by using a mechanical shredder to break down plastic into tiny pieces, then sends it to a reactor where it’s soaked in hot ammonium hydroxide. Plastics like PET, commonly used in disposable water bottles, break down at this point. Other plastics used in military food packaging, like polyethylene and polypropylene, are sent to a separate reactor where they’re exposed to even higher temperatures and a lack of oxygen.
Under these conditions, polyethylene and polypropylene are converted into compounds that can be upcycled into fuels and lubricants. David Schonard, a chemical engineer at Michigan Technological University who oversaw this part of the project, has founded a startup called Resurgent Innovation to commercialize some of this technology. (Schonard says other members of the research team are working on additional patents related to other parts of the system.)
