For almost half a decade, a team of scientists led by Brett Helms of Berkeley Lab: The Molecular Foundry, have been working on an eco-friendly plastic that can be recycled over and over again, without any drop in quality.
They have finally succeeded by engineering E. coli bacteria to help create an infinitely recyclable plastic called poly(diketoenamine), or PDK.
The bacteria turns sugar from plants into the raw materials for biorenewable plastics.
According to the study, published in Nature Sustainability, unlike conventional plastics, PDK can be infinitely deconstructed into pristine building blocks and formed into new products with no loss in quality.
While PDK was initially made from petrochemicals, the researchers have managed to create a new type of PDK out of a molecule called triacetic acid lactone, or bioTAL. It is this starting material that is produced by the manipulated E. coli bacteria.
The use of bioTAL enables the production of a PDK with almost 80% bio-content. The scientists strongly feel that they will be able to create PDK out of 100% bio-content in the future.
This eco-friendly plastic can be used for a variety of products such as adhesives, building materials, and flexible items like computer cables or watch straps.
“Tough thermosets,” or rigid plastics made through a curing process, is also a possibility with PDK.
Adding bioTAL into the mix expanded PDK’s working temperature range by up to 60 degrees Celsius compared to the petrochemical version.
This means PDK can be used in items that need specific working temperatures like sports gear and automotive parts (bumpers or dashboards).
Due to the growing amount of plastic being produced every year and abysmally low percentage of it getting recycled, the production to recycling ratio is actually getting lower.
In the US in 2018, less than 9% of plastic was being recycled. By 2021, less than 5% was being recycled.
The problem is that conventional plastic degrades upon recycling. Also, we use so many different types of plastic today which cannot be melted together, that collecting and sorting them for recycling becomes even more expensive.
This is why the need to get innovations like PDK out there feels more urgent than ever before. The PDK technology is available for licensing and collaboration to anyone interested.
Berkeley Labs’ 2021 study showed that PDK could be commercially viable if produced on a larger scale.
The researchers say “even modest improvements to the production process” “could soon make bio-based PDK plastics that are both cheaper and emit less CO2 than those made with fossil fuels”.
