Butter from air: researchers capture CO₂ and turn it into artificial fat

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Farming with dairy cattle is not considered very sustainable. Cows need space, large amounts of feed and water and are also surprisingly industrious producers of methane emissions. A research group from the USA is therefore now looking to replace some of the products that previously came from ruminants with a special method: Capturing CO₂ from the air is to be combined with the production of climate-friendly food.

Fats to feel good without a cow

As the New Scientist reports, the process was first presented in the journal Nature Sustainability in the fall of 2023 - in a study entitled "Foods without Agriculture". Behind the project are earth system researchers Steven J. Davis from the University of California, Irvine, Kathleen Alexander, who was working at Orca Sciences at the time, and other colleagues at universities in Waterloo and Shenzhen as well as at Breakthrough Energy. Orca and Breakthrough are both companies from the US state of Washington, which received financial backing from Microsoft co-founder Bill Gates.

The project has now been bundled into the start-up Savor. It advertises with appetizing images and the slogan "Feel Good Fats": The company's aim is to "produce delicious and versatile fats from a raw material [that] is available in abundance: Carbon". These are "real fats", not a substitute product. Gates, who is also involved in Savor, personally enthused about the idea in spring: in his blog GatesNotes, but also in a video showing him cooking.

Like petrochemicals - plus rosemary

One of the first products Savor is aiming for is an alternative to butter. Biology is not needed for this, says Alexander to New Scientist, who was appointed CEO of the start-up and previously worked as a materials scientist and consultant for climate solutions before becoming project director at Orca. There has long been a substitute for butter in the form of margarine (which many people find less tasty). But even this is not considered sustainable enough by Savor, as the cultivation of its raw materials, such as vegetable fat, also requires a lot of land and water.

The process used by Savor is more reminiscent of the petrochemical industry than the food industry. The company makes use of the fact that fats are known to consist of carbon and hydrogen atoms of different lengths. Savor now extracts CO₂ from the ambient air and hydrogen from water, heats and oxidizes them to create triglycerides together with glycerine. Water and an emulsifier are added, then some carotene for the color. A hint of rosemary oil is supposed to provide the "grassy" taste.

Does it taste good and is it healthy?

Gates, who is not above trying out new sustainable products, has already tried the end product. "I couldn't believe it wasn't butter," he was quoted as saying. The price should not be too expensive either. According to Alexander, it can already be expected to compete with butter. However, before it goes on sale - the USA is planned as the first market - official approval must be obtained.

Savor boss Alexander believes that the switch to synthetic fats could halve the climate footprint compared to regular agriculture. However, removing CO₂ from the air is only a side effect. It remains problematic whether people would buy such a product and consider it healthy. Artificial trans fatty acids have a bad reputation. That is why Savor is concerned with creating a healthy product that people "really like". There is also another problem: the potential disruption of entire sectors of the economy. "Although scaling up such synthesis systems could disrupt the agricultural economy and depends on consumer acceptance, the huge potential greenhouse gas reductions and reduced land and water use represent a realistic opportunity to offset the environmental footprint of agriculture in the coming decade," write Alexander and co. in their paper.

(bsc)