Sustainable nylon production thanks to gut bacteria

Nylon production could be revolutionised by the discovery that bacteria can incorporate a key chemical into the process without emitting harmful greenhouse gases.

 

Scientists have developed a sustainable method for producing one of the world’s most valuable industrial chemicals – known as adipic acid – which is a key ingredient in the manufacture of nylon. More than two million tonnes of this versatile substance, which is used to make clothing, furniture and parachutes, are produced worldwide each year, with a market value of around 5.5 billion euros.

The industrial production of adipic acid is generally based on fossil fuels. It is associated with the emission of large quantities of nitrous oxide, a greenhouse gas whose environmental impact is three hundred times greater than that of carbon dioxide. A sustainable production method is urgently needed to reduce environmental damage.

Scientists at the University of Edinburgh in England may have discovered a promising solution. They modified the genetic code of the gut bacterium Escherichia coli (E. coli) in the laboratory. The modified cells were cultured in liquid solutions containing a naturally occurring chemical known as guaiacol. This substance is the main component of a compound that gives plants their shape. The result: after a 24-hour incubation period, the modified bacteria converted the guaiacol into adipic acid without producing nitrous oxide. Of interest to industry is the fact that, according to the scientists, this environmentally friendly approach can be scaled up to enable the production of adipic acid on an industrial scale.

Lead author of the study, Jack Suitor, a PhD student at the School of Biological Sciences at the University of Edinburgh, said: “This is the first time that adipic acid has been produced directly from guaiacol, one of the largest untapped renewable resources on the planet. This could completely transform the way nylon is produced.” 

“If bacteria can be programmed to produce nylon from plant waste,” says Dr Stephen Wallace, the study’s principal investigator – something that is currently not possible using conventional chemical methods – “we will have to ask ourselves what else they might be capable of and where the limits lie. We’re all familiar with the use of microbes to ferment food and beer – now we can ferment materials and medicines. The potential of this approach to creating a sustainable future is very promising.”

Reference

Jack T. Suitor, Simon Varzandeh and Stephen Wallace, One-Pot Synthesis of Adipic Acid from Guaiacol in Escherichia coli, ACS Synthetic Biology (2020), https://doi.org/10.1021/acssynbio.0c00254