Scientists say microbes can be engineered to create renewable plastics

July 27 (UPI) -- Scientists said Thursday they have collaborated to create engineered microbes to make recyclable plastics that can replace the current non-recyclable products made by petrochemicals.

The research on recyclable plastics performed at the Department of Energy's Lawrence Berkeley National Laboratory Molecular Foundry, the Joint BioEnergy Institute and the Advanced Light Source was published in the peer-reviewed publication Nature Sustainability.

Scientists said they had successfully created microbes to make biological alternatives for the starting ingredients in an infinitely recyclable plastic known as poly(diketoenamine), or PDK.

PDKs can be used for adhesives, flexible items like computer cables or watch bands, building materials, along with rigid plastics made through a curing process.

"This is the first time that bioproducts have been integrated to make a PDK that is predominantly bio-based," Brett Helms, a staff scientist at the Molecular Foundry, said in a news release.

"And it's the first time that you see a bio-advantage over using petrochemicals, both with respect to the material's properties and the cost of producing it at scale."

Researchers needed four years during which collaborators manipulated E. coli to turn sugars from plants into some of the starting materials, which included a molecule known as triacetic acid lactone, or bioTAL, and produced a PDK with roughly 80% bio-content.

The researchers said they were surprised to find that incorporating the bioTAL into the material expanded its working temperature range by up to 60 degrees Celsius compared to the petrochemical version.

They said that led to using PDKs in items that need specific working temperatures, including sports gear and automotive parts such as bumpers or dashboards.

"We've demonstrated that the pathway to 100% bio-content in recyclable plastics is feasible," said Jeremy Demarteau, a project scientist on the research team. "You'll see that from us in the future."

The study follows up on the 2021 environmental and technological analysis showing that PDK plastic could be commercially competitive with the plastic used today if produced on a large scale.

"We can't keep using our dwindling supply of fossil fuels to feed this insatiable desire for plastics," Jay Keasling, a professor at the University of California, Berkeley, senior faculty scientist in Berkeley Lab's biosciences area, said in the release.

"We want to help solve the plastic waste problem by creating materials that are both bio-renewable and circular -- and providing and incentive for companies to use them.

"Then, people could have the products they need for the time they need them before those items are transformed into something new."