Edinburgh researchers convert plastic waste into L-DOPA

Researchers have demonstrated a new way to produce L-DOPA, a widely used Parkinson’s disease treatment, by converting discarded plastic bottles into pharmaceutical compounds using engineered bacteria.

The method, developed by scientists at the University of Edinburgh, uses genetically modified E. coli to transform components derived from polyethene terephthalate (PET) – the plastic commonly used in food and drink packaging – into L-DOPA.

The work shows how biological systems can be engineered to convert post-consumer plastic waste into medically valuable molecules.

The findings, published in Nature Sustainability, point to a potential new pathway for manufacturing medicines while simultaneously addressing plastic pollution.

Dr Liz Fletcher, Director of Impact and Deputy CEO at Industrial Biotechnology Innovation Centre (IbioIC), emphasised the significance of the research: “This project highlights the potential of biology to reshape the way we think about waste.

“Turning plastic bottles into a Parkinson’s drug isn’t just a creative recycling idea; it’s a way of redesigning processes that work with nature to deliver real-world benefits.

“By demonstrating that a harmful material can be converted into something that improves human health, the team is proving that sustainable, high-value applications of biology are both practical and effective.”

A biological route from PET waste to medicine

PET is one of the most widely produced plastics globally, with roughly 50 million tonnes manufactured each year.

Because it is derived from fossil resources and difficult to recycle efficiently, much of it ultimately ends up in landfills, incinerators, or the environment.

In the new study, researchers first broke down PET waste into its core chemical building block, terephthalic acid. The team then engineered E. coli to convert this molecule into L-DOPA via a series of enzymatic reactions.

L-DOPA is a cornerstone therapy for Parkinson’s disease, a neurological disorder characterised by the progressive loss of dopamine-producing neurons in the brain. The drug acts as a precursor to dopamine, helping alleviate symptoms such as tremors, stiffness and impaired movement.

According to the researchers, the engineered pathway demonstrates that plastic waste can serve as a feedstock for synthesising complex pharmaceutical molecules.

Rethinking pharmaceutical manufacturing

Traditional pharmaceutical production often relies on petrochemical feedstocks and energy-intensive chemical synthesis. The Edinburgh team says their approach could offer a more sustainable alternative by recycling carbon contained in plastic waste.

By using microbes to convert plastic-derived compounds into drugs such as L-DOPA, the process could reduce dependence on fossil-fuel-based raw materials while creating value from materials that would otherwise be discarded.

The study also highlights a broader concept known as bio-upcycling – the use of biological systems to transform waste into higher-value products rather than simply recycling materials back into lower-grade plastics.

Researchers suggest that similar microbial engineering strategies could eventually be applied to manufacture a range of chemicals, including ingredients used in cosmetics, flavourings, fragrances and industrial materials.

Moving toward industrial applications

The research team reports that they successfully produced and isolated L-DOPA at a preparative scale, demonstrating that the method works beyond small laboratory experiments.

The next phase will focus on improving the efficiency of the microbial conversion process and assessing how well it could scale to industrial production. Further studies will also evaluate the environmental and economic performance of the system compared with existing manufacturing methods.

If scaled successfully, the approach could contribute to a circular production model in which waste plastics are converted into high-value chemicals and pharmaceuticals.

Research funding and collaboration

The project received funding from UK Research and Innovation (UKRI) and the IBioIC. Industry partner Impact Solutions contributed testing and laboratory support.

The work was conducted within the Carbon-Loop Sustainable Biomanufacturing Hub (C-Loop), a £14m research initiative exploring ways to transform industrial waste streams into useful chemicals and materials.

The hub is supported by the Engineering and Physical Sciences Research Council (EPSRC), part of UKRI.

Commercialisation support for the research is being provided through Edinburgh Innovations, the University of Edinburgh’s technology transfer and business development arm.

Implications for plastic waste and drug production

The ability to convert PET waste into L-DOPA illustrates how biotechnology could link two major challenges: reducing global plastic pollution and developing more sustainable supply chains for medicines.

While further optimisation is required before the process can be adopted commercially, the study provides early evidence that microbial manufacturing platforms may help reshape how Parkinson’s disease treatment and other pharmaceutical compounds are produced in the future.