Scientists have discovered a way to convert plastic waste into painkillers using genetically modified bacteria (designer bacteria). Although the research is still at the laboratory level, it is expected that enhancing the technology could provide a solution to both the growing problem of plastic waste and the reduction of fossil fuels worldwide.
Researchers at the University of Edinburgh and ASTK announced on the 23rd (local time) that they have succeeded in extracting paracetamol (acetaminophen), a key ingredient in painkillers and antipyretics, from discarded plastic bottles using Escherichia coli in the international journal Nature Chemistry.
Professor Steven Wallace from the University of Edinburgh noted in the paper that "most people are unaware that paracetamol is extracted from petroleum" and said, "This research shows that it is possible to produce painkillers and antipyretics in a sustainable manner by integrating chemistry and biology and to purify plastic waste."
Paracetamol, the main ingredient in renowned antipyretics such as Tylenol and Panadol, is synthesized using materials derived from the decomposition of petroleum or coal, like the majority of other drugs. Scientists believe that replacing this ingredient with waste like plastic could be a groundbreaking method to simultaneously resolve two major environmental issues.
The research team successfully converted polyethylene terephthalate (PET), used globally for food packaging and bottles, into paracetamol using genetically modified Escherichia coli. They reported that during this process, they discovered a chemical reaction known as Lossen rearrangement, which had not been observed in nature, to have biocompatibility.
This reaction, first discovered by German chemist Wilhelm Lossen in 1872, involves the rearrangement process that converts hydroxamic esters into isocyanates and then into amines. The term biocompatibility means that it can perform biological reactions without harming living cells. This is the first reported case of a synthetic reaction, the Lossen rearrangement, successfully integrating with a cell's metabolic system without causing harm to the cells or impairing biological function.
The researchers designed a process that begins with acyl hydroxamic esters to produce para-aminobenzoic acid (PABA), which is essential for E. coli growth and DNA synthesis. This Lossen rearrangement process originally required harsh laboratory conditions, but was carried out naturally in genetically modified E. coli.
The researchers confirmed that E. coli could grow without a catalyst when cultured with various transition metals and without PABA. Additionally, it was found that phosphates played a catalytic role in producing PABA.
Typically, PABA is produced from other substances within the cell. However, the E. coli used in the experiment was genetically modified to block this pathway, necessitating the use of PET-based materials. When PET plastic is decomposed into terephthalic acid, PET-1 is produced through the Lossen rearrangement, which serves as a precursor (the material in a chemical reaction) for producing PABA.
The researchers investigated whether E. coli could create a new metabolic pathway to produce paracetamol from PET-1. To synthesize paracetamol, they added two genes, one derived from mushrooms and another from soil bacteria. The research team found that by culturing this form of E. coli at 37 degrees, paracetamol was produced with an 83% yield. They also reported achieving a maximum yield of 92% within 24 hours.
The researchers emphasized that this study is significant as it represents a process of converting plastic waste into biological materials. It is noteworthy for being the first to combine synthetic processes in chemistry with biological metabolic processes. In particular, this research has been praised for making encouraging progress in addressing the significant issues of plastic pollution and the dependence on fossil fuels in the drug manufacturing process. It is estimated that plastic generates over 350 million tons of waste annually, of which 56 million tons is produced for industrial use, with 80% being single-use. It takes between 20 to 500 years to decompose.
Recently, scientists have been utilizing microorganisms as a method to convert plastic beyond mere decomposition into useful materials. This approach, which combines biological processes with chemical reactions, aims to reduce plastic pollution and also manufacture pharmaceuticals. The pharmaceutical manufacturing process generates a massive carbon footprint, emitting 55% more carbon than the automotive industry; however, this new method nearly eliminates carbon emissions.
Further research is needed to produce painkillers on a commercial scale using this method. Professor Wallace stated, "This new production method can help reduce plastic pollution and decrease dependence on fossil fuels used in the manufacture of widely used pharmaceuticals," adding, "I think this is a very interesting starting point for upcycling plastic waste." This research was funded by the pharmaceutical company AstraZeneca.
References
Nature Chemistry (2025), DOI: https://doi.org/10.1038/s41557-025-01845-5