Bacteria commonly used in the biotech industry could soon feed on CO2 instead of sugar, turning climate pollution into carbon-neutral biofuels or even food. In a decade-long study, scientists at Israel’s Weizmann Institute of Science engineered for the first time a form of E. coli that can consume carbon dioxide.
E. coli, better known publicly for strains that cause food poisoning, is already used to make drugs like insulin. (The gene for producing human insulin is added to the bacteria, which then pumps out the drug inside its cells.) But the process normally involves feeding the bacteria sugar as it grows. The researchers tweaked the bacteria so that it could eat CO2, using both genetic engineering and “assisted evolution” in the lab.
The milestone means that it could become easier to make more products from the world’s most significant greenhouse gas. E. coli is relatively easy to use in manufacturing. “The biotechnology industry has become very, very good at manipulating the genome of E. coli in order to optimize it as a production platform,” says Shmuel Gleizer, a researcher at the Weizmann Institute of Science and first author of a new paper about the study published in the journal Cell.
Some startups are already beginning to use microbes to transform CO2 into products; Air Protein, launched in November, uses CO2 to make protein for alternative meat. But microbes that these new companies use are proprietary. “They’re using microbes that are much harder to engineer than E. coli, and therefore the variety of products that these microbes can manufacture from the capture of CO2 is very limited compared to E. coli,” he says.
The research also suggests that other organisms that are heterotrophs, meaning that they can’t produce their own food, could also be altered to consume CO2. That could potentially include yeasts, which are also commonly used in biotech manufacturing.
If the production process uses renewable energy, “then we will basically have negative emissions of CO2,” says Gleizer. Some products may be carbon neutral—if the bacteria make jet fuel, for example, the planes that use it will still emit greenhouse gases, but no more than the CO2 that was originally used to produce the fuel. The CO2 could potentially come from direct air capture.
Several steps are still necessary before it’s clear that the process is feasible. When the current strain of the bacteria feeds on CO2, it grows much more slowly than if it was eating sugar; the researchers think that future versions can be faster. The E. coli will also have to be further modified to produce specific products. And production equipment in biotech factories might also have to change. “There’s still a long way to optimize this process,” says Gleizer.