Scientists from the Department of Energy's Lawrence Berkeley National Laboratory engineer microbes to create an infinitely recyclable plastic, setting the stage for a sustainable future.
Image Credit: Extarz via Shutterstock / HDR tune by Universal-Sci
Plastic waste has become a dire environmental issue. Despite worldwide efforts to promote recycling, most plastics don't make the cut due to their finite and polluting nature.
However, a new breakthrough could change this narrative as researchers from the Lawrence Berkeley National Laboratory have successfully bioengineered microbes to produce an infinitely recyclable plastic known as poly (diketoenamine), or PDK.
The team published their findings in the peer-reviewed science journal Nature Sustainability.
bio-based PDK versus normal plastics
According to the project's lead scientist at the Molecular Foundry, Brett Helms, he and his team produced a predominantly bio-based PDK for the first time ever, offering a distinct advantage over petrochemicals in terms of cost-efficiency and material properties.
What sets PDK apart from traditional plastics is its ability to be
deconstructed back into its pristine building blocks without losing quality, ready to be remade into new products. Though the initial versions of PDK were derived from petrochemicals, this latest innovation allows these ingredients to be bioengineered using microbes.
Over the past four years, the researchers manipulated E. coli to turn plant sugars into some of the starting materials – specifically a molecule known as triacetic acid lactone (bioTAL). The result was a PDK with approximately 80% bio-content.
Potential applications
PDKs have a broad range of potential applications, from adhesives and building materials to flexible items such as computer cables and watch bands. Notably, when the bioTAL was incorporated into the material, it expanded its working temperature range by up to 60 degrees Celsius, opening doors to use PDKs in items requiring specific working temperatures, like sports gear and automotive parts.
As the plastic waste problem continues to grow – with estimates from the United Nations Environment Program suggesting we produce about 400 million tons per year, a number projected to rise to over 1 billion tons by 2050 – solutions are more critical than ever.
Dealing with the global plastic waste issue has proven to be a a mountainous task (Image Credit: Mohamed Abdulraheem via Shutterstock / HDR tune by Universal-Sci)
Jay Keasling, a professor at UC Berkeley: “We can’t keep using our dwindling supply of fossil fuels to feed this insatiable desire for plastics. We want to help solve the plastic waste problem by creating materials that are both biorenewable and circular – and providing an 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.’’
This discovery follows an environmental and technological analysis from 2021, which showed that if produced on a large scale, PDK plastic could compete commercially with conventional plastics.
The team found that with modest improvements to the production process bio-based PDK plastics could be produced that are both cheaper and emit less CO2 than those made with fossil fuel.
Moving forward, the team plans to focus on improving the production process, including accelerating the rate of sugar conversion to bioTAL and using bacteria capable of transforming a wider variety of plant-derived sugars and compounds. They are also considering powering their facilities with renewable energy, making the whole process more sustainable from start to finish.
Sources and further reading:
Biorenewable circularity in polydiketoenamine plastics (nature sustainability)
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