Scientists have successfully used microorganisms to produce components for recyclable plastics, providing an environmentally friendly alternative to petrochemicals. Plastic waste poses a huge challenge because most plastics cannot be recycled and many are manufactured using limited, environmentally harmful petrochemicals.
However, this is starting to change. Researchers have recently succeeded in producing an infinitely recyclable biological substitute for the basic material polydiketonolamine plastic (PDK) through microbial engineering technology.
The innovative discovery, recently published in the journal Nature Sustainability, is a collaboration between three institutions at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) – the Molecular Foundry and the Joint Bioenergy Institute (JBEI). The result of a collaborative effort with experts in advanced light sources.
”This is the first time biological products have been put together to make a primarily biologically based PDK,” said Brett Helms, a Molecular Foundry staff scientist who led the project. “It’s also the first time you’ve seen that, with Compared with using petrochemical products, bio-based products have advantages in terms of material properties and large-scale production costs.”
Unlike traditional plastics, PDK can be repeatedly broken down into its original building blocks and made into new products without reducing quality. PDK initially uses building blocks derived from petrochemicals, but these ingredients can be redesigned and produced using microorganisms. Now, after four years of work, collaborators have manipulated E. coli to convert sugars in plants into part of the starting material—a molecule called triacetolactone, or bioTAL—and produced a product with a biological content of about 80 % of PDK.
“We have proven that the path to 100% biocontent in recyclable plastics is possible,” said Dematour, a project scientist involved in the team that developed the biopolymer. “You will see this from us in the future. PDK
can be used in a variety of products, including adhesives, flexible items like computer cables or watch straps, construction materials, and “tough thermosets,” which are hard plastics made through a curing process. The researchers were surprised to find that adding biological TAL to the material expanded its operating temperature range by 60 degrees Celsius compared to the petrochemical version. This opens the door to using the PDK in items that require specific operating temperatures, including sports equipment and automotive parts such as bumpers or dashboards.
The United Nations Environment Program estimates that about 400 million tons of plastic waste are generated globally every year, and this number is expected to climb to more than 1 billion tons by 2050. Of the 7 billion tons of plastic waste that has been generated, only about 10% has been recycled, with most being discarded in landfills or incinerated.
“We can’t continue to use dwindling fossil fuels to satisfy our insatiable appetite for plastics,” said Jay Keesling, professor at the University of California, Berkeley, senior scientist in biosciences at Berkeley Lab, and CEO of JBEI. “We hope that by creating both Biorenewable and recyclable materials to help solve the plastic waste problem and incentivize companies to use these materials. This way, people can get the products they need when they need them, and then transform these products into something new.”
The research released today also builds on a 2021 environmental and technology analysis that showed PDK plastic could compete commercially with conventional plastics if produced at scale.
”Our new results are very encouraging,” said JBEI Vice President Schenn, who is a scientist in Berkeley Lab’s energy technologies area. “We found that with modest improvements to the production process, we can quickly create bio-based PDK plastics. , which not only costs less but also emits less CO2 than plastics made using fossil fuels.”
These improvements include speeding up the rate at which microorganisms convert sugars into bioTALs and using sugars derived from plants that convert more and other compounds as well as powering devices with renewable energy.