Generally, there are two types of organisms on the planet: autotrophs and heterotrophs. Autotrophs like plants create their own food source from inorganic materials such as carbon dioxide and sunlight. On the other hand, heterotrophs such as animals and bacteria have to consume other organic materials to survive.

Scientists have been trying to create heterotrophs that consume inorganic materials in the laboratory in hopes of producing strains of bacteria that consume carbon dioxide and, hopefully, help curb climate change-contributing carbon emissions or perhaps create a foundation for carbon-neutral production. Unfortunately, results often result in limited success.

Carbon Dioxide-Eating Bacteria

In a new study published in Cell, researchers report the successful creation of an E. coli strain than consumes Carbon dioxide instead of organic compounds. Researchers first gave the bacteria genes that allow photosynthetic organisms to convert carbon dioxide, but it did not work. The team instead inserted a gene that would allow the bacteria to glean energy from a compound called formate, but the E. coli still refused to swap sugar meals with carbon dioxide.

Researchers then continued to culture generations of the modified E. coli for a year, giving them fewer sugars and carbon dioxide concentrations 250 times higher than those in the Earth ’s atmosphere, in hopes that they will eventually evolve to have the new diet.

After 200 days, the first carbon dioxide-dependent bacteria emerged.

Carbon Emission

An important question, perhaps, is whether the milestone can directly help to curb the climbing carbon emissions in the Earth’s atmosphere. The problem as of now, according to researchers, is that the process produces more carbon dioxide than the bacteria consumes. Further, the researchers note that it will take a lot more work to see the possibilities for industrial use.

That said, the result of the study is a major stepping stone for sustainable production sources, and could provide the framework for future innovations on carbon-neutral energy sources.

For instance, in the future, carbon dioxide-eating E. coli strains could be used to create organic carbon molecules as biofuels or for food production. By creating products from organic sources, the process would have lower carbon emissions and would even have the potential to remove carbon dioxide from the air.

Carbon Neural Production

Even today, E. coli is already being used to create products such as synthetic versions of insulin and human growth hormones. With the team’s work, the number of products created by E. coli could increase, although they do not see this happening any time soon.

For now, the researchers are looking into using renewable electricity as energy sources to hopefully reduce the excessive carbon dioxide release.

“This feat is a powerful proof of concept that opens up a new exciting prospect of using engineered bacteria to transform products we regard as waste into fuel, food or other compounds of interest,” senior author Ron Milo of the Weizmann Institute of Science said. “It can also serve as a platform to better understand and improve the molecular machines that are the basis of food production for humanity and thus help in the future to increase yields in agriculture.”

E. coli bacteria.
E. coli bacteria is seen in an image taken by an electron microscope. Reuters