Scientists have created a strain of the lab workhorse bacteria that grows by consuming carbon dioxide (CO2) instead of sugars or other organic molecules.
According to a paper published in Cell, the bacterium (full name Escherichia coli) has been engineered by scientists to consume carbon dioxide instead of sugar which could be used to produce biofuels in the future.
This was done by scientists at the Weizmann Institute of Science in Israel to convert carbon dioxide to energy for themselves while generating biomass that can be used as biofuel.
Scientists said they hope to tap synthetic life-forms to convert atmospheric carbon dioxide, into food, fuel and organic chemicals that humans can use.
Although while the study comes with a major limitation, the research team hopes their work can provide a foundation for carbon-neutral energy sources in the future. Notably, because previous attempts, like a 2016 effort to synthesize sugar from CO2 in bacteria, saw little success.
Ron Milo who led the research explained that the team didn’t expect to be able to make such remarkable changes to the bacteria’s genome.
How the bacteria work
According to reports, Milo and his team in the latest work used a mix of genetic engineering and lab evolution to create a strain of E. coli that can get all its carbon from CO2.
First, they gave the bacterium genes that encode a pair of enzymes that allow photosynthetic organisms to convert CO2 into organic carbon.
Plants and cyanobacteria power this conversion with light, but that wasn’t feasible for E. coli. Instead, Milo’s team inserted a gene that lets the bacterium glean energy from an organic molecule called formate.
Even with these additions, the bacterium refused to swap its sugar meals for CO2. To further tweak the strain, the researcher’s cultured successive generations of the modified E. coli for a year, giving them only minute quantities of sugar, and CO2 at concentrations about 250 times those in Earth’s atmosphere.
They hoped that the bacteria would evolve mutations to adapt to this new diet. After about 200 days, the first cells capable of using CO2 as their only carbon source emerged. And after 300 days, these bacteria grew faster in the lab conditions than did those that could not consume CO2.
The CO2-eating, or autotrophic, E. coli strains can still grow on sugar and would use that source of fuel over CO2, given the choice, says Milo. Compared with normal E. coli, which can double in number every 20 minutes, the autotrophic E. coli are laggards, dividing every 18 hours when grown in an atmosphere that is 10 percent CO2. They are not able to subsist without sugar on atmospheric levels of CO2 currently 0.041percent.
People’s reaction to the new discovery
Milo and his team hope to make their bacteria grow faster and live on lower levels of CO2. They are also trying to understand how E. coli evolved to eat CO2, changes in just 11 genes seemed to allow the switch, and they are now working on determining how.
Shmuel Gleizer, the research first author and a researcher at the Weizmann Institute of Science, in a press release expressed the difficulty they had to go through to achieve this scientific feat.
Frank Sargent, a researcher at Newcastle University, described the technology as one with endless possibilities, saying:
This type of directed evolution is already a Nobel prize-winning type of science and this is a terrific example of why.
Cheryl Kerfeld, a bioengineer at Michigan State University in East Lansing and the Lawrence Berkeley National Laboratory in California, expressed his support for the work stating it is a milestone ahead and is evidence of the power of melding engineering and evolution to improve natural processes.
