E. coli consuming carbon dioxide may offer hope against global warming
Researchers have created a new version of Escherichia coli, the lab’s most studied bacterium, that grows by consuming CARBON DIOXIDE instead of sugar or other organic molecules.
This work is an important milestone because it succeeded in drastically altering the metabolism of E. coli. In the future, it could be used to make organic carbon molecules or produce food, using E. coli, which consumes CO2. Products made in this way can remove CO2 gas from the air, as well as will have lower CO2 emissions compared to traditional production methods.
How did the scientists do the experiment?
The researchers used a mix of genetic engineering and laboratory evolution to create an E. coli strain that can get all its carbon from CO2. They first transferred genes into E. coli encode a pair of enzymes that allow photosynthetic organisms to convert CO2 to organic carbon. Plants and cyanobacteria perform this conversion with light energy, but this is not suitable for E. coli. So instead, they transferred a gene to E. coli that allows it to take energy from an organic molecule called formate.
Heterotrophic E. coli (left) produce biomass from sugar, but lab-evolved autotrophic E. coli from the new study (centre) use CO2 instead. The authors envision autotrophic E. coli that use renewable energy and have no net carbon emissions in the future (right) (Gleizer et al., 2019).
In the beginning, despite all these additions, the bacteria refused to exchange the sugar for CO2. So the researchers cultivated E. coli for one year in succession under CO2 at concentrations of about 250 times atmospheric values. The goal was to force the bacteria to develop mutations to adapt to this new diet. About 200 days later, the first cells appeared that could use CO2 as the sole carbon source.
What can we hope for?
This study showed that very radical changes can be made in the metabolism of an organism in the laboratory. More importantly, it has been shown that it is possible to develop organisms that can produce various products using CO2, one of the greenhouse gases in the atmosphere. In short, making production by taking CO2 from the atmosphere instead of giving CO2 to the atmosphere during production is promising as an alternative method in the fight against global warming in the future.
Reference:
Gleizer et al. Conversion of Escherichia coli to Generate All Biomass Carbon from CO2. Cell, 2019