Our thinking

Carbon fixation

24 February, 2020

Carbon fixation

Escherichia coli (or E. coli, as it’s more commonly known) is a bacteria species that, although mostly harmless and part of the normal gut flora, has some strains that are notorious for causing serious food poisoning in their hosts.

However, its bad guy status may not be entirely deserved. The living world is largely divided into autotrophs (like plants) that convert CO₂ into biomass and heterotrophs (like us, and most bacteria) that consume organic compounds. Last week, however, scientists in Israel manipulated E. coli in lab conditions so that the bacteria are able to fix CO₂ from the atmosphere by stimulating the Calvin cycle (the process central to photosynthesis). This means they were eventually able to rely entirely on CO₂ from the air and formate to generate biomass. There was excitement from a scientific perspective – “I find it fundamentally amazing that an organism which evolved over billions of years to live a heterotrophic lifestyle can so quickly and completely change into an autotroph” said Dave Savage, and we enthusiastically agree – but this could also have big implications for biofuel and food production.

You may be wondering, “don’t plants already do that?” and you’re right. And this process still needs work to be viable at scale. But where it holds promise is in providing an additional source of food and fuel without having the same space requirements or impact on soil and broader ecosystems that plants do, in the same way that algae-based biofuels can (particularly when combined with wastewater treatment systems). E. coli salad, anyone?