Hydrogen-Oxidizing Bacteria as a Catalyst for a Post-Agricultural Food System

Dietary Transition as a Prerequisite for Sustainable Food Systems

Global food production occupies more than one third of the Earth’s terrestrial surface and contributes over 30% of global greenhouse gas (GHG) emissions (Laukkanen 2021). These pressures are intensified by interconnected global challenges, including rapid population growth, accelerating climate change and a range of socio political instabilities that further complicate efforts to ensure food system resilience (Galanakis 2024).

Within this context, the discourse surrounding the future of food has gained prominence in both scientific and societal arenas. A growing body of research identifies dietary change as one of the most effective strategies for simultaneously improving human health and reducing environmental impacts. Consequently, a fundamental transformation of prevailing dietary patterns has become imperative, with the EAT Lancet Commission (2019, 26) highlighting the need for substantial shifts toward more sustainable consumption models.

A central component of this transformation involves reducing global meat consumption, which has risen markedly in recent decades. Livestock production accounts for nearly two thirds of agricultural GHG emissions and approximately 78% of methane emissions, largely due to enteric fermentation processes (Laukkanen 2021, 7-8). Despite the clear environmental rationale, this transition is hindered by the deep cultural significance of meat within Western dietary norms, where it is valued not only for its nutritional qualities but also for its sensory and symbolic attributes (Elzerman et al. 2013, 707). Further research indicates that consumer reluctance toward plant based diets is often associated with self oriented value structures and negative attitudes toward meat substitutes (Laukkanen 2021, 14-15).

Nevertheless, consumer awareness plays a crucial role in enabling systemic change. Modifying dietary behaviors can substantially lower environmental impacts while also reducing the risk of major non communicable diseases, including cardiovascular disease, cancer and type 2 diabetes (Laukkanen 2021, 13-14). To facilitate this transition, it is essential to strengthen the integration of environmental and health education, supported by the development of evidence based guidelines and public services that foster broad societal alignment around health promoting and ecologically responsible dietary practices (Galanakis 2024).

Innovative Protein Sources to Enable a Dietary Transition

A fundamental challenge underlying the previously discussed issues is the low efficiency of converting feed into animal-derived protein. Yet, because dietary protein is essential for human nutrition, plant-based alternatives have emerged as a viable strategy to address this inefficiency, with global demand for such products increasing steadily (Smil 2002, 305). Several analyses indicate that dietary shifts could reduce greenhouse gas (GHG) emissions and land use associated with current diets by up to 50%. However, while plant-based meat substitutes offer clear environmental benefits, their high degree of processing and implications for overall food well-being mean that they cannot be regarded as a complete or optimal solution (Hallström et al. 2015, 1-3.).

In response to these limitations, a range of innovative technologies focused on producing proteins from unconventional biological sources – such as algae, yeasts and molds – has attracted growing interest across both research and industrial sectors. Among these emerging approaches, single-cell proteins (SCP), also referred to as microbial proteins (MP), represent one of the most promising and widely investigated alternatives. SCPs consist of microbial biomass cultivated under controlled conditions in intensive, closed systems known as bioreactors. Such systems allow for stable growth parameters, efficient nutrient use, minimal environmental impact and the complete absence of pesticide or antibiotic requirements. Additional advantages, when compared to conventional agricultural protein production, include high protein content rich in essential amino acids, minerals and vitamins; efficient nitrogen and phosphorus cycling with negligible environmental leakage; and minimal land requirements, enabling production in marginal, industrial or urban settings (Ciani et al. 2021, 1-2.).

Among the most sustainable forms of single cell protein (SCP) are those generated by hydrogen oxidizing bacteria (HOB), a group of chemolithoautotrophic microorganisms capable of fixing carbon dioxide (CO₂) into cellular biomass. This assimilation is driven by the energy released during the oxidation of molecular hydrogen with oxygen. The overall stoichiometric expression for aerobic CO₂ fixation via H₂ oxidation is:
H₂ + O₂ + CO₂ → Biomass + H₂O.
In process configurations where both H₂ and O₂ are supplied through water electrolysis, the integrated system becomes functionally analogous to oxygenic photosynthesis. Under such conditions, the overall transformation can be represented as:
H₂O + CO₂ + Energy → Biomass + O₂.
This analogy underscores the potential of HOB based SCP production as an electrically driven, land independent biochemical route for converting inorganic carbon into high value biomass. (Pander et al. 2020, 21.).

Because HOB-based production can be entirely decoupled from fossil energy – relying instead on renewable electricity to generate H₂ and O₂ – this approach offers significant potential for large-scale sustainable protein production. Yields may reach several hundred tonnes of biomass per hectare per year, and further reductions in production costs are expected as renewable energy and related technologies continue to advance. Despite these advantages, the commercial viability of SCP technologies still faces important challenges. First, products must meet stringent nutritional and safety criteria, requiring regulatory approval from bodies such as the European Food Safety Authority (EFSA). Second, SCP-derived foods must achieve market competitiveness and consumer acceptance, which includes developing favorable sensory qualities alongside robust nutritional and environmental performance (Ciani et al. 2021, 4, 10.).

Solar Foods as a Model of the Circular Carbon Economy

Solar Foods is highlighted among companies producing food from CO₂; the article notes that Solein, 80 % protein “out of thin air”, is already being served in Singapore (e.g., gelato and pasta) and illustrating how gas fermentation proteins are entering real menus. There is also the broader wave of startups using microbial processes to turn CO₂ into edible proteins (Turrell 2023, 1363.)

Picture 1. Solein ice cream (Image: © Solar Foods 2024).

Founded in 2017, Solar Foods produces Solein by cultivating a natural, non modified single cell organism in a bioreactor supplied with carbon dioxide, hydrogen and minerals; the biomass is then dried into a yellow powder with a typical composition of ~78–80% protein and micronutrients (e.g., vitamin B12, iron). The company’s first factory in Finland (launched April 2024) targets up to 160 t/year and integrates electrolysis derived H₂ and CO₂ (including direct air capture), positioning the process as decoupled from photosynthesis and soil based agriculture (Solar Foods 2025.).

Although the positive aspects are innumerable, there are still some challenges to overcome to be able to spread on the market, the main one related to regulatory approvals. Solein was approved as a food ingredient in Singapore in October 2022, by the Singapore Food Agency (SFA), which allowed its marketing and sale in the territory. In September 2024 it was listed on the Nasdaq First North Growth Market Finland and obtained GRAS self-certification in the United States (Solar Foods 2025; IBC Finland 2024.).

Towards a New Era of Food Production

Despite the substantial environmental and technological advantages associated with Solein and other hydrogen based microbial proteins, several challenges must be addressed before widespread market adoption can occur. The most significant of these relates to regulatory approval processes. Solein received its first major regulatory endorsement in October 2022, when the Singapore Food Agency (SFA) approved it as a food ingredient, enabling its commercial distribution within Singapore. The product subsequently obtained GRAS (Generally Recognized as Safe) self-certification in the United States and was listed on the Nasdaq First North Growth Market Finland in September 2024.

Approval within the European Union is anticipated for 2026, positioning Solein as a potential cornerstone in the development of a new food era – one that could ultimately operate independently of traditional agriculture.

References

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Pander, B., Mortimer, Z., Woods, C., McGregor, C., Dempster, A., Thomas, L., Maliepaard, J., Mansfield, R., Rowe, P. & Krabben, P. 2020. Hydrogen oxidising bacteria for production of single-cell protein and other food and feed ingredients. Eng. Biol. 4,  21-24. Cited 18 Mar 2025. Available at https://doi.org/10.1049/enb.2020.0005

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Turrell, C. 2023. From air to your plate: tech startups making food from atmospheric CO2. Nature Biotechnology. Vol. 41, 1362–1364. Cited 19 Mar 2025. Available at https://www.nature.com/articles/s41587-023-01992-5

Authors

Pietro Savioli is an Italian freethinker whose work explores non‑anthropocentric ecological and anthropological questions. In recent years, he has focused on researching and communicating the influence of lobbying activities on environmental issues.

Anne‑Marie Tuomala is a senior lecturer at LAB University of Applied Sciences and previously taught Pietro Savioli during his exchange studies at LAB.

Illustration: © Solar Foods 2024

Reference to this article

Savioli, P. & Tuomala, A.-M. 2026. Hydrogen-Oxidizing Bacteria as a Catalyst for a Post-Agricultural Food System. LAB Pro. Cited and date of citation. Available at https://www.labopen.fi/lab-pro/hydrogen-oxidizing-bacteria-as-a-catalyst-for-a-post-agricultural-food-system/