Protein made from air and electricity

In plain language

Some bacteria can grow on gases instead of sugar. A group called hydrogen-oxidising bacteria takes in hydrogen and carbon dioxide and uses them to build its own cells, which are rich in protein. Companies grow these microbes in closed tanks, supply the gases and a few minerals, and then dry the harvest into a powder. The hydrogen is usually made by splitting water with electricity, so the process runs on power, water and air rather than on farmland.

The appeal is that this route needs far less land than growing soybeans or crops for animal feed. Whether it is better for the climate depends mostly on where the electricity comes from, and the published life-cycle studies show that clean power is essential. One producer reports that its powder is about 80% protein by dry weight and that Singapore has approved it as a food. The published cost figures are modelled, and the two studies are not directly comparable: the 2024 model gives a minimum selling price of $2,070 per tonne for animal feed, while the 2025 model projects EUR 5.5 to 6.1 per kg for single-cell protein in 2028. The sources used for this profile do not report how much protein the large plants actually make.

Technical explanation

Hydrogen-oxidising bacteria (HOB) are aerobic microbes that convert atmospheric carbon dioxide and hydrogen into biomass through gas fermentation. The Trends in Biotechnology review by Bernal-Cabas and colleagues (2026) notes that this approach is already used for food-grade single-cell protein. In the techno-economic model by Jean and Brown (2024), hydrogen and oxygen come from wind-powered water electrolysis, and carbon dioxide is captured from corn ethanol production. The modelled product is an animal feed meant to replace fishmeal or soybean meal.

The life-cycle and cost evidence is narrow and depends on assumptions. Jarvio and colleagues (2021) used empirical data from a small-scale Finnish producer and found that electricity was the largest contributor to impacts; hydropower gave 87.5% lower global warming potential than the average Finnish grid mix. Fasihi and colleagues (2025) model renewable-electricity protein at optimal sites, projecting costs of EUR 5.5 to 6.1 per kilogram in 2028, falling to EUR 2.1 to 2.3 per kilogram by 2050, on a roadmap to 30 million tonnes of protein a year. These are projections rather than operating costs.

The main open question is scale-up. The producers' stated figures are capacities: up to 160 tonnes a year for Solar Foods' Factory 01, and 20,000 tonnes of protein for the first commercial-scale facility of Calysseo, as Calysta announced in 2023. Neither source reports actual annual output. The Trends review presents engineering these bacteria into cell factories for precision fermentation as a path forward, not as a demonstrated result.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Limitations and open problems

• No regulator's own record was checked for this profile. The Singapore approval date, the US self-affirmed GRAS status and the FDA GRAS status for FeedKind all come from company statements.
• Self-affirmed GRAS is a company's own safety conclusion. The company page does not say whether a regulator reviewed it.
• The Jean and Brown (2024) figures are scenario results. The 0.73 kg CO2-equivalent per kg protein is an 'as low as' value under wind-electrolysis and corn-ethanol assumptions, and the study concerns animal feed rather than food protein.
• The main life-cycle study (Jarvio and colleagues, 2021) used data from one small-scale producer, and its results depend strongly on the electricity source. The 87.5% reduction is for hydropower and is not typical of most grids.
• The 2025 cost projections are modelled roadmaps for 2028 to 2050 at optimal sites with favourable renewable resources. They are not operating data.
• Stated capacities (up to 160 tonnes a year for Factory 01; 20,000 tonnes of protein for Calysseo's first commercial-scale facility) are not output figures. The sources used here do not report actual annual production for either plant.

Possible future uses

Timeline

1. Jul 2021Jarvio and colleagues publish an attributional life-cycle assessment of hydrogen-oxidising bacteria protein, using empirical data from a small-scale producer. Sources: [2]
2. Sept 2022The Singapore Food Agency gives Solein its first novel food regulatory approval, according to the producer. Sources: [5]
3. 20 Feb 2023Calysta announces that the US FDA Center for Veterinary Medicine has granted GRAS status to FeedKind for salmonid feed at up to 18% of the diet. Sources: [7]
4. Feb 2024Jean and Brown publish a techno-economic analysis of gas-fermented single-cell protein for animal feed in Environmental Science and Technology. Sources: [1]
5. 10 Feb 2025Fasihi and colleagues publish a global potential study of renewable-electricity single-cell protein in Nature Communications. Sources: [3]
6. Apr 2026Trends in Biotechnology publishes a review on gas precision fermentation with hydrogen-oxidising bacteria. Sources: [4]

Futures this could help bring about

How far away?

Food made from air and electricity

Pilots · 4 of 8 steps done

Related breakthroughs

• Singapore approves Solein, a protein powder grown from CO2 and hydrogen (26 Oct 2022)

Glossary

Gas fermentation

Growing microbes in a tank on gases such as hydrogen, carbon dioxide or methane instead of on sugars.

Single-cell protein

Protein-rich biomass harvested from microbial cells, such as bacteria, yeasts or fungi, for use as food or feed.

Self-affirmed GRAS

A US route in which a company concludes on its own that an ingredient is generally recognised as safe, without a formal FDA review.

Minimum selling price

The lowest price at which a modelled product would cover its costs, including a set return on investment.

Sources

1. peer reviewed paper
   Techno-Economic Analysis of Gas Fermentation for the Production of Single Cell Protein
   Alexandra B. Jean, Robert C. Brown. Environmental Science & Technology, Feb 2024. DOI: 10.1021/acs.est.3c10312. Accessed 22 Oct 2026.
2. peer reviewed paper
   An attributional life cycle assessment of microbial protein production: A case study on using hydrogen-oxidizing bacteria
   N. Järviö, N. L. Maljanen, Y. Kobayashi et al.. Science of the Total Environment, Jul 2021. DOI: 10.1016/j.scitotenv.2021.145764. Accessed 22 Oct 2026.
3. peer reviewed paper
   Global potential of sustainable single-cell protein based on variable renewable electricity
   Mahdi Fasihi, Fatemeh Jouzi, Petri Tervasmäki et al.. Nature Communications, 10 Feb 2025. DOI: 10.1038/s41467-025-56364-1. Accessed 22 Oct 2026.
4. review article
   Food production from air: gas precision fermentation with hydrogen-oxidising bacteria
   M. Bernal-Cabas, K. Kumar, O. Terpstra et al.. Trends in Biotechnology, Apr 2026. DOI: 10.1016/j.tibtech.2025.08.003. Accessed 22 Oct 2026.
5. company announcement
   Solein
   Solar Foods Oyj, 22 Oct 2026. Accessed 22 Oct 2026.
6. company announcement
   Factory 01
   Solar Foods Oyj, 22 Oct 2026. Accessed 22 Oct 2026.
7. company announcement
   FeedKind® Protein Wins FDA GRAS Status for Use in Aquaculture
   Calysta, 20 Feb 2023. Accessed 22 Oct 2026.

Revision history

3 changes since this profile was created.