Newcastle team engineers E. coli to make chemicals from waste CO2

The research, published in Applied and Environmental  Microbiology raises the possibility of converting atmospheric CO₂ to commodity chemicals.

Normally, an enzyme in E. coli catalyses the reverse of this reaction—production of H₂ and CO₂ from formic acid. In nature, the latter is best known as a type of vinegar compound ants use to ward off predators.

To reverse the normal reaction in E. coli, the investigators got the bacteria to switch out molybdenum, a metal that is normally a critical part of the enzyme, for tungsten, by growing the bacteria in an excess of the latter. "This is fairly easy to do as E. coli cannot readily tell the difference between the two," said principal investigator Dr Frank Sargent. This changed changed the properties of our enzyme so that it was locked in CO₂ capturing mode he added.

The investigators used a special pressurized bioreactor filled with H₂ and CO₂ to make the gases available to the microbes. "It worked—the bacteria could grow under gas pressure and generate formic acid from the CO₂," said Sargent.