Power-to-Vitamins: producing folate alongside protein from renewable electricity and CO₂

One of the recurring criticisms of Power-to-Food is that producing protein alone is not the same as producing food. Humans need a balanced intake of macronutrients, micronutrients and vitamins. Protein synthesised from CO₂ and renewable hydrogen is impressive, but real-world food applications often require fortification with vitamins and minerals that the base process does not produce. A research team at the University of Tübingen has now shown that this gap can be closed inside the bioreactor itself.

A two-stage bioreactor that makes protein and vitamin B9 at once

Working with co-author Michael Rychlik from the Technical University of Munich, Prof. Largus Angenent’s Environmental Biotechnology Group at the University of Tübingen published a study in Trends in Biotechnology in September 2024 demonstrating a power-to-vitamins extension of their earlier power-to-protein system. The system runs in two coupled stages.

In Stage A, the acetogenic bacterium Thermoanaerobacter kivui takes hydrogen and CO₂ and produces acetate – the same simple two-carbon molecule that gives vinegar its characteristic acidity. The hydrogen is produced by water electrolysis using renewable electricity. The CO₂ is recycled carbon. T. kivui was chosen because, unlike the Clostridium bacterium the team had previously used, it can synthesise its own folate (vitamin B9) and does not require external vitamin supplementation. That detail matters: if you have to add B9 to make B9, the process is not net-additive. With T. kivui, the system actually produces more folate than it consumes.

In Stage B, ordinary baker’s yeast (Saccharomyces cerevisiae) feeds on the acetate produced in Stage A, plus oxygen. The yeast produces protein, and – demonstrated for the first time in this study – it also produces folate de novo from acetate as the sole carbon source, at rates comparable to what the same yeast produces from sugar.

The numbers

The harvested dried yeast, according to the team’s analysis, meets the daily B9 requirement at around 6 grams of intake. On the protein side, 85 grams of the yeast provides about 61 percent of an adult’s daily protein requirement, compared to 34 percent from an equivalent mass of beef, 25 percent from pork, and 38 percent each from fish and lentils. The yeast does require post-treatment to reduce compounds (nucleotides, purines) that could increase the risk of gout if consumed in excess; treated yeast still delivers around 41 percent of the daily protein requirement at the same mass – still competitive with conventional sources.

The inputs are renewable electricity, water, recycled CO₂, and small quantities of mineral nutrients. No land. No agricultural runoff. No methane emissions. No fertiliser. The output is a single ingredient that can serve as a vegan base for meat alternatives while also delivering one of the essential B-vitamins that vegan diets often lack.

Why this is interesting for Power-to-X

The Tübingen-TUM result is one example of a broader pattern: the same fundamental building blocks of Power-to-X – green hydrogen, recycled CO₂, renewable electricity – can be routed into very different end products. We have written previously about Solar Foods and the commercial side of Power-to-Food, where Solein is now produced at industrial scale in Finland using hydrogen-oxidising bacteria. The Tübingen approach uses a different microbial architecture – an acetate intermediate followed by yeast – but the underlying logic is identical. Renewable electricity becomes hydrogen, hydrogen becomes a one-carbon building block, building blocks become food.

The conceptual significance of the vitamin extension is that it widens the nutritional envelope of microbial protein. If gas fermentation can produce protein and essential vitamins from the same renewable inputs, the technology moves closer to being a complete food ingredient rather than just a protein supplement. The same approach could in principle be extended to other B-vitamins and other micronutrients that microbes naturally synthesise.

Honest caveats

This is laboratory-scale work. The next steps the team has identified – scaling up production, food safety assessment, techno-economic analysis, market interest gauging – are precisely the steps that determine whether a promising bioprocess becomes a viable food ingredient. The same scaling questions apply here as for Solar Foods or any other Power-to-Food system: cost of hydrogen, cost of CO₂ capture, energy intensity of the bioreactor, depreciation of capital equipment, regulatory pathway to food approval.

It is also worth being clear about what the technology displaces and what it does not. The authors explicitly state that the goal is not to outcompete farmers, but to allow conventional agriculture to concentrate on vegetables, fruit and crops while bioreactor-derived protein and vitamins substitute for some of the land-intensive feed and animal protein production. The honest framing is complementarity, not replacement.

SPIN Perspective

Power-to-Vitamins is a useful reminder that Power-to-X is not confined to the fuels and chemicals sectors that dominate the public conversation. The same scientific and infrastructural foundations – cheap renewable electricity, scalable electrolysis, recycled carbon, controlled bioreactor environments – underpin a much wider product range than e-SAF or e-methanol alone.

For a country like Switzerland with significant food import dependence and a strong pharmaceutical and biotech sector, the implications matter. The companies that supply bioreactor equipment, control systems, fermentation media, electrolysers, and CO₂ capture units are largely the same companies whether the end product is a synthetic fuel or a synthetic vitamin. An industrial base built around any of these end products is, to a significant extent, transferable across them. That is one of the strategic arguments for being broadly present in the Power-to-X value chain rather than betting on a single application.

Source: Schmitz, Kreitli, Obermaier, Weber, Rychlik, Angenent, “Power-to-vitamins: producing folate (vitamin B9) from renewable electric power and CO2 with a microbial protein system”, Trends in Biotechnology, September 2024. Coverage: University of Tübingen, EurekAlert.

🤖 AI transparency: This text and its visual were created using AI, reviewed and approved by a human.