SAN DIEGO — A new type of bioplastic could help reduce the plastic industry’s environmental footprint.
The solution to plastic pollution might lie with bacterial spores from a strain of Bacillus subtilis, according to nanoengineer Han Sol Kim with the UC San Diego Jacobs School of Engineering.
“This looks like just random powder but actually they are alive. They are even very smart,” Kim said.
Kim helped develop a biodegradable form of a thermoplastic polyurethane, a soft yet durable commercial plastic used in footwear, floor mats, cushions and memory foam. They filled the TPU with bacterial spores that, when exposed to nutrients present in compost, germinate and break down the material at the end of its life cycle.
“[Bacillus subtilis is] also widely found in some good, healthy fermented foods such as kimchi or yogurt, so this is totally safe bacteria,” Kim said. “As soon as this spore-embedded plastic meets the soil, they will start degradation.”
Adam Feist engineered the bacterial spores to survive the high temperatures used to produce the plastic.
“These were the good ones because they had the ability to form these spores, first of all; they had this protein shield that they could survive," Feist said. "And two, they actually could eat the plastic so they had these great properties already that we could further enhance.”
Janis Jones is one of the leaders for Rise Above Plastics at the San Diego chapter of the Surfrider Foundation. She says most plastic pollution at sea starts back on land from overflowing landfills and litter and a living plastic that truly breaks down over time would be a great help.
“We want to stop it at the source. We don’t want it to get to the beaches," Jones said. "We want to put ourselves out of business when it comes to beach cleanups.”
Rise Above Plastics also advocates for the reduction of single-use plastics by using data collected at beach cleanups. Jones hopes working on the problem from the beach to the lab creates real impact.
“We need innovation," she said. "We need the way that we use and dispose of plastics to be better.”
Researchers still need to study what gets left behind after the living plastic degrades, but they hope to create a better option on a larger scale soon.
“It’s just really cool application. You can use these teeny tiny things to do work to help benefit society,” Feist said.
“We envision that if we can make self-degrading plastic that naturally breaks down when it touches soil, we can potentially mitigate the accumulation of plastics in nature,” Kim said.
The spores also serve as a strengthening filler, similar to how rebar reinforces concrete.