Researchers have found a way to turn plastic waste into paracetamol, also known as acetaminophen, using a common bacterium.

The breakthrough, developed by researchers at the University of Edinburgh’s Wallace Lab, has found a way to make pain relief both cheaper and more sustainable.

A researcher checking growth of a culture of E. coli in the Wallace Lab. Image: University of Edinburgh.

At present, paracetamol is made from fossil fuels like crude oil, using energy-intensive processes that release large amounts of carbon emissions. 

Each year, thousands of tons of fossil fuels are burned to power factories that produce paracetamol and other medicines. 

Bacteria, not barrels, deliver

In contrast, the new method uses genetically reprogrammed E. coli, a harmless bacterium, to turn terephthalic acid, a compound found in plastic bottles, into paracetamol.

The process works at room temperature and produces almost no carbon emissions.

Researchers used a fermentation technique similar to beer brewing, converting industrial polyethylene terephthalate (PET) plastic waste into paracetamol in less than 24 hours.

In lab tests, 90% of the chemical output was pure paracetamol, showing strong early results.

In the process, the researchers discovered that a chemical reaction called a Lossen rearrangement – previously unseen in nature – could occur inside living cells.

They had converted PET plastic into an intermediate compound which, when incubated with genetically modified E. coli, transformed into PABA, a molecule bacteria typically use to make DNA. 

Brewing drugs from plastic

Because the bacteria’s usual pathway for making PABA was blocked, they were forced to rely on the PET-based feedstock. Remarkably, the reaction occurred spontaneously inside the cells, catalysed by naturally occurring phosphate, even though it normally requires harsh lab conditions. This suggests plastic waste can be biologically converted into essential chemicals.

The researchers then took it a step further, inserting two additional genes – one from mushrooms and another from soil bacteria – allowing the E. coli to convert PABA into paracetamol.

This innovation could also help tackle global plastic pollution.

PET plastic, a strong, lightweight material used in food packaging and drink bottles, makes up more than 350 million tons of waste every year. While it is technically recyclable, most methods still create products that eventually re-enter the waste stream.

“This work demonstrates that PET plastic isn’t just waste or a material destined to become more plastic – it can be transformed by microorganisms into valuable new products, including those with potential for treating disease,” said Professor Stephen Wallace, UKRI Future Leaders fellow and chair of Chemical Biotechnology.

Further development is needed before the method can be scaled up for commercial production, said the team.

But the early results show strong potential for creating affordable, low-emission alternatives to traditional drug manufacturing.

According to the experts, the groundbreaking research is a significant step forward in combining biology and chemistry to build cleaner, circular systems for drug manufacturing, while also reducing waste, greenhouse gas emissions and reliance on fossil fuels.

“Engineering biology offers immense potential to disrupt our reliance on fossil fuels, build a circular economy and create sustainable chemicals and materials, and we would invite potential collaborators to get in touch,” said Ian Hatch, head of consultancy at Edinburgh Innovations (EI), the university’s commercialisation arm. 

The study was published in Nature Chemistry, and funded by the UK’s EPSRC and AstraZeneca, and supported by EI.