Michigan Tech associate professor Stephen Techtmann came up with a way to extract value from plastic waste with the help of certain kinds of bacteria.

Plastics to protein: Portable innovation combats waste and hunger

Would you voluntarily eat a plastic bag? How about a plastic water bottle? As unappealing and unhealthy as that sounds, a Michigan Technological University scientist’s innovation could lead to people consuming protein powder that started out as plastic waste. 

“The waste that we often throw out is still quite valuable,” Stephen Techtmann, Michigan Tech associate professor, told Centered. “The problem is we just have to figure out how to extract value from that waste.”

Techtmann came up with a way to extract value from plastic waste with the help of certain kinds of bacteria. They eat oily substances and can be used to clean up contaminants. Conventional plastics are petroleum-derived products, so using oil-eating bacteria to eliminate them seemed like a natural fit.

This type of bacteria is easily found in water and soil environments globally. The Michigan Tech team focused on using those from the Great Lakes region.

“The cultures we’re working with that are showing the most promise are coming from some compost at a farm up here in the Upper Peninsula of Michigan, so it’s really locally sourced,” Techtmann said. “There’s a really neat biological diversity in the Great Lakes area that makes this really great place to start.” 

The process begins by enlisting assistance from chemical engineers to break down plastic into an oily substance. The bacteria eat the oil and break it down in about a day. Once they are plump, the bacteria are dried and turned into a protein powder. 

“Bacterial cells on a molecular level look a lot like the foods that we normally eat,” Techtmann said. “They have the proteins, carbohydrates, and vitamins that we would normally get from our food.”

Two problems, one solution

In addition to eliminating plastic waste, the innovation could aid global hunger mitigation. 

The quick rate at which the bacteria grow and process plastics makes the solution ideal for situations where a lot of food is needed quickly, such as a disaster relief scenario. The researchers plan to turn the innovation into an integrated system that can be deployed in a variety of places, including rural areas.

“As a scientist, something that gets me excited is if we can take those organisms, turn them into something that can be commercialized, and really help society,” Techtmann said.

The researchers are also keeping energy, portability, and affordability in mind during development. They’re trying to ensure the system can run on low power so it functions in disaster areas where power was knocked out or in places with inconsistent power supplies. 

Building the system from readily available components — even some that are available on Amazon — keeps costs down. They want it to be small enough to fit into a pickup truck bed.

Readily available resources

The bacteria are readily available, and they grow and multiply quickly. The lab just needs a few bacterial cells to start, and then the cells “make millions and millions more of themselves,” in a process that Techtmann likens to cultivating a sourdough bread starter.

For now, the lab is focusing on feeding the bacteria three commonly used plastics: polyethylene terephthalate (PET), which is found in water bottles, and various types of polyethylene and polypropylene, which are commonly used as food packaging and grocery bags. Other plastics could be a possibility in the future.

“The bacteria that we’re using are quite flexible in what we can feed them,” Techtmann said. “Even though we might be feeding them broken down plastic bags one day and the next day broken down plastic bottles, they seem to equally eat both types of plastics very well.”

Lab equipment
Credit: Michigan Technological University / Courtesy

What’s next

Right now, Techtmann’s team can make the protein powder and do it in high quantities. They’re working with the FDA to demonstrate that the protein powder is safe to eat and exhibits nutritional value. They hope to achieve approval in the next couple of years.

Educating people about the system and getting them to accept that they’re not eating plastic will take work. The concept of making protein powder from plastic and bacteria is “almost science fiction” and a tough one for some people to swallow, Techtmann said.

The team aims to build industrial partnerships to bring the product to market. They’re also investigating making some of the technology open source so others can repeat the process and build systems in resource-limited areas.

The system can be tailored to create other products besides protein powder. Modifying the process can prompt the bacteria to produce fuels and lubricants.

Some aspects of commercialization depend on how the team scales the operation. For example, keeping the operation small, like a disaster relief scenario, leads down a different path than scaling the system to the size of a recycling plant.

“Our goal is really to make it as widely available as possible,” Techtmann said. “If I can even make a small contribution to helping to address plastic waste, that is exciting.”