Researchers have devised a way to make a commonly used pain and fever reduction medication from plastic waste. Yes, you read that right.
They used genetically engineered microbes to transform a molecule obtained from polyethylene terephthalate (PET) plastic into paracetamol. Also known as acetaminophen, paracetamol is the active ingredient in widely available over-the-counter pain and fever reduction medicines, sold under brand names like Tylenol, Panadol or Dolo.
Upward of three-quarters of the common medicines that we rely on are currently derived from fossil carbon. “Paracetamol is a really good example of that,” Stephan Wallace, the study’s corresponding author and professor of chemical biotechnology at the University of Edinburgh, Scotland, told Mongabay in a video call. “It’s currently derived from benzene, which is a really unsustainable petrochemical, by industrial processes that emit, quite frankly, unacceptable amounts of greenhouse gases into the atmosphere.”
Nearly all plastic is derived from fossil fuels and very little is recycled. The vast majority of plastic waste ends up in landfills, incinerators or the environment, especially oceans. So, the researchers wanted to see if they could turn a problem waste product into something useful.
They first discovered that a commonly used synthetic chemical reaction called the Lossen rearrangement can actually occur in living bacterial cells. The reaction has previously only been observed in labs but not in nature.
The researchers found that phosphate within bacterial cells can catalyze this Lossen rearrangement, converting terephthalic acid — derived from the breakdown of PET plastic — into para-aminobenzoic acid (PABA), inside the bacteria. They then engineered the bacteria by introducing genes from soil bacteria and mushrooms, enabling the bacteria to convert PABA into paracetamol.
“And not only did that give us a sustainable way to make paracetamol in biology for the first time, but we were able to connect that to plastic waste so that we could complete that whole sort of transformation of waste into paracetamol,” Wallace said.
The researchers could convert more than 92% of the degraded PET plastic, commonly used in food packaging and textiles, into paracetamol using this method. The emissions from this new process “are fractional” compared with those from the current paracetamol manufacturing process, Wallace said.
The researchers acknowledge that converting plastic into paracetamol will not solve the enormous plastic crisis. However, Wallace said it’s a step in the right direction. He said he sees plastic waste as an untapped resource that can be transformed into something useful, though it will take time.
“It’s going to be a while until you can go to the bar and get your beer in a plastic cup, take it home, put a bacterium in it and turn it into your hangover cure the next day.”
Banner image of plastic bottles ready for recycling. Image by Hans Braxmeier via (Pixabay Content License).
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