It's easy to see discarded plastic as nothing more than waste. Much of it ends up in landfill, breaking down into microplastics that seep into water supplies and threaten the environment, and potentially human health. But what if the same plastic waste could instead be transformed into life-saving medicines?
In a recent study published in Nature Sustainability , scientists at the University of Edinburgh have shown that everyday plastic waste is not just an environmental burden but an untapped source of embedded carbon - the carbon atoms locked within plastic's chemical structure. They demonstrated that engineered E coli bacteria can convert polyethylene terephthalate (PET) - commonly used in bottles and food packaging - into levodopa, a key treatment for Parkinson's disease.
This approach offers a promising alternative to traditional levodopa production, which relies on multiple fossil fuel-based chemical steps and is energy intensive, costly, and carbon heavy.
Parkinson's affects more than 10 million people worldwide and becomes more common as populations age. Levodopa remains the most effective treatment for managing the disease's hallmark symptoms, including tremors and muscle stiffness. As demand for the drug rises, finding sustainable ways to produce levodopa has become increasingly urgent.
In previous studies, the same Edinburgh researchers showed that plastic can be turned into paracetamol , a common painkiller. In the lab, they converted up to 90% of the plastic from a one-litre PET bottle into paracetamol in just 24 hours - an amount roughly the same as nine 500mg paracetamol tablets.
Early work in this area began to show that plastics could serve as chemical feedstocks for medicine. In 2022 , researchers at the University of Southern California demonstrated that polyethylene (PE) - a different plastic from PET, commonly used in plastic bags and films - could be broken down by engineered fungi into useful compounds, including building blocks for antibiotics, antifungals and cholesterol-lowering drugs.
Building on this, more recent studies have focused on higher-value drugs. For example, a collaborative study led by the University of St Andrews with partners in the Netherlands and Germany showed that PET plastic could be converted into starting materials for cancer therapies and drugs that stop uncontrolled bleeding.
These results show that it's possible to turn everyday plastic waste into useful medicines. This approach could cut down on the need for fossil fuels and support a more sustainable, circular economy where waste is reused instead of thrown away.
The road ahead
Turning this lab breakthrough into industrial-scale production won't happen overnight. Engineers must develop cost-effective manufacturing processes, and regulators will need to be satisfied that the products meet strict safety standards.
Collecting enough plastic waste is another challenge, since it has to compete with traditional fossil fuels. Success will require long-term investment and close teamwork between scientists, industry and policymakers.
So, while the idea is exciting, it's still at an early stage. It offers a glimpse of what might be possible in the future, where biology and engineering help turn some types of plastic waste into medicines.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
