Turning plastic into medicine: Closing the loop on pharma production

Scientists at the University of Edinburgh have developed a new method to produce paracetamol using plastic waste as a starting point. By genetically engineering Escherichia coli, the researchers were able to convert terephthalic acid, an intermediate obtained from recycled polyethylene terephthalate (PET) plastic, into the common painkiller through microbial fermentation.

Can synthetic biology offer new routes to pharmaceutical production that are both sustainable and scalable? While in the early stages, this work adds to a growing body of research suggesting that engineered microbes could play a role not only in creating new therapies but in rethinking how essential medicines are made.

Plastic to paracetamol, inside the study

Turning plastic into a pharmaceutical ingredient isn’t just a matter of swapping one raw material for another. It requires rethinking the chemistry and, in this case, reprogramming a bacterium to carry it out.

At the heart of the Edinburgh team’s approach is terephthalic acid, a compound released when PET plastic is broken down. Instead of relying on petroleum-derived chemicals, the researchers fed terephthalic acid directly to E. coli, but not just any strain. They engineered the microbe to follow a carefully constructed pathway that could transform the plastic-derived compound into paracetamol.

The process, described in a paper published in Nature Chemistry today, takes place at room temperature, produces minimal emissions, and avoids the use of fossil-based chemical synthesis. According to the authors, it achieved a conversion yield of nearly 90% in under 24 hours. The study was supported by AstraZeneca and the U.K.’s Engineering & Physical Sciences Research Council (EPSRC) funding program.

Rethinking drug manufacturing

The production of active pharmaceutical ingredients (APIs) still depends heavily on petrochemical processes. Even paracetamol, a simple and widely used painkiller, is typically made through a multi-step synthesis starting with phenol, which itself is derived from benzene, a crude oil product. The standard route involves nitration, hydrogenation, and acetylation steps under high-temperature and solvent-intensive conditions.

While efficient and long-established, this model ties medicine production to fossil fuel availability and contributes to industrial emissions, especially when applied to high-volume generics like paracetamol, which are consumed globally in vast quantities.

In contrast, fermentation-based production is already the norm for biologics and many complex molecules, from insulin to antibiotics and monoclonal antibodies. The Edinburgh team’s work raises the possibility that small molecules, too, could be made through microbial systems. 

One of the strengths of microbial engineering is its modularity. Pathways can potentially be adapted or redirected to suit different targets. While this paracetamol pathway won’t replace current manufacturing overnight, it could be a step toward more flexible, lower-emission models for drug production.

There’s also growing momentum behind such efforts. Pharmaceutical companies are under pressure to decarbonize supply chains, reduce solvent waste, and report on environmental performance as part of broader ESG (environmental, social, and governance) commitments. AstraZeneca, which supported this study, has made sustainability a stated priority, pledging to halve its carbon footprint by 2030 in its 2023 sustainability report. Whether that impulse is driven by industry guidelines or a genuine vision for more sustainable supply chains, the actions still have a positive impact.

From plastic to pharma: Is a circular model viable?

While the microbial production of paracetamol from PET is promising in the lab, several hurdles stand in the way of real-world application. One of the main challenges is the variability of plastic waste. PET derived from bottles or packaging can differ in quality and composition, which complicates its use as a consistent feedstock for pharmaceutical manufacturing.

Regulatory constraints are another limiting factor. Producing APIs through fermentation is not new; E. coli has been used to produce insulin since the early 1980s. But applying similar processes to small molecules, especially from non-traditional sources like plastic, would require careful validation and likely new oversight frameworks.

Economically, chemical synthesis of paracetamol remains efficient and inexpensive. A microbial route would need to offer a clear advantage, through lower emissions, supply chain resilience, or feedstock accessibility, for it to become competitive at scale.

That said, the paracetamol study doesn’t exist in isolation. A growing number of research projects are exploring how PET waste can be used to make useful compounds, including biodegradable plastics and industrial chemicals. These efforts use many of the same principles: engineered microbes, enzyme pathways, and fermentation. 

If plastic can be turned into a drug as widely used as paracetamol, it raises a reasonable question: could other drugs follow?

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