E. coli That Eats Carbon, Rather Than Emitting It

Researchers at Israel’s Weizmann Institute of Science in Rehovot have created a strain of Escherichia coli (E. coli) that metabolizes carbon dioxide rather than sugar, a “milestone” achievement that may one day play a role in lowering emissions produced in biofuel and food production, reports the journal Nature.

Plants, as well as photosynthetic cyanobacteria, use photosynthesis to turn CO2 plus light into the carbon-based building blocks of life. But Nature explains that efforts to harness the process in a lab setting, then turn the life forms into “biological factories,” has been slow, since the organisms “can be hard to genetically modify”.

By contrast, the “lab workhorse” E. coli is “relatively easy to engineer, and its fast growth means that changes can be quickly tested and tweaked to optimize genetic alterations.” Until now, however, dreams of industrializing the use of E. Coli to synthesize the building blocks of carbon-based products like biofuels had themselves been stymied by the fact that “the bacterium prefers to grow on sugars such as glucose—and instead of consuming CO2, it emits the gas as waste.”

So systems biologist Ron Milo and colleagues “spent the past decade overhauling E. coli’s diet,” first creating a strain (somewhat) willing to chow down on CO2 in 2016. But the bugs still vastly preferred sugar, and it wasn’t until very recently that Milo and his team at Weizmann created a strain willing and able to subsist entirely on carbon dioxide.

There is still much work to be done, Nature writes, noting that the latest E. coli are not yet “able to subsist without sugar on atmospheric levels of CO2—currently 0.041%.”

But the bacterium is already used to synthesize “versions of useful chemicals such as insulin and human growth hormone,” Nature says. Milo’s team hopes its work will expand the bacterium’s repertoire to food and renewable fuels, “but he doesn’t see this happening soon.”