Hydrogenotroph

Hydrogenotrophs are organisms that are able to metabolize molecular hydrogen as a source of energy.

An example of hydrogenotrophy is performed by carbon dioxide-reducing organisms^[1] which use CO₂ and H₂ to produce methane (CH₄) by the following reaction:

• CO₂ + 4H₂ → CH₄ + 2H₂O

Other hydrogenotrophic metabolic pathways include acetogenesis, sulfate reduction, and other hydrogen oxidizing bacteria. Those that metabolize methane are called methanogenic.^[2] Hydrogenotrophs belong to a group of organisms known as methanogens, organisms that carry out anaerobic processes that are responsible for the production of methane through carbon dioxide reduction. Methanogens also include a group of organisms called methylotrophs, organisms that can use single-carbon molecules or molecules with no carbon-carbon bonds.^[3]

Background Information

Hydrogenotrophic bacteria were first experimented with by NASA in the 1960s in order to find a replenishable food source.^[4] Hydrogenotrophic bacteria have been found to have a high protein and carbohydrate content and have been a guiding principle in developing sustainable agricultural methods.^{[citation needed]} Experimentation has revealed that hydrogenotrophic bacteria can convert carbon dioxide into food more rapidly than plants, making them an efficient and sustainable alternative to implement into plant-based high-protein diets and as a substitute in products that use plant extracts and oils.^[5]

In September 2022, finnish biotech startup Solar Foods received its first food regulatory approval^[6] from the Singapore Food Agency (SFA) for a protein supplement (Solein) derived from hydrogenotrophic microorganisms,^[7] and has since started production in a commercial-scale facility.^[6]

Hydrogenotrophs are commonly found in the human gut, along with other fermentative bacteria which live in symbiosis with one another.^[4] They are also found in soils and in sediments of freshwater and marine ecosystems around the world.^[8]

See also

• Single cell protein^[9]

References

1. Stams, J.M., and Plugge, C.M. (2010) The microbiology of methanogenesis. In Reay, D., Smith, P., and Van Amstel, A., eds. Methane and Climate Change, 14-26.
2. Vianna, M. E.; Holtgraewe, S.; Seyfarth, I.; Conrads, G.; Horz, H. P. (2008). "Quantitative Analysis of Three Hydrogenotrophic Microbial Groups, Methanogenic Archaea, Sulfate-Reducing Bacteria, and Acetogenic Bacteria, within Plaque Biofilms Associated with Human Periodontal Disease". Journal of Bacteriology. 190 (10): 3779–3785. doi:10.1128/JB.01861-07. PMC 2394984. PMID 18326571.
3. Costa, Kyle C; Leigh, John A (2014-10-01). "Metabolic versatility in methanogens". Current Opinion in Biotechnology. Cell and Pathway Engineering. 29: 70–75. doi:10.1016/j.copbio.2014.02.012. ISSN 0958-1669. PMID 24662145.
4. "Retro spacetech microbes revived to make food from CO2". Futures Centre. 2016-08-11. Retrieved 2019-12-09.
5. "A forgotten Space Age technology could change how we grow food". 24 August 2017. Retrieved 2019-12-09.
6. "Solein®". Solar Foods. Retrieved 2024-06-15.
7. Jolly, Jasper (2024-04-19). "Eating light: Finnish startup begins making food 'from air and solar power'". The Guardian. ISSN 0261-3077. Retrieved 2024-06-15. Solar Foods instead uses the same renewable electricity from the sun to split water apart. It then feeds the hydrogen and oxygen to the microbes in a brewing vessel, plus carbon dioxide captured from the air from the company's office ventilation system.
8. Gaci, Nadia; Borrel, Guillaume; Tottey, William; O’Toole, Paul William; Brugère, Jean-François (2014-11-21). "Archaea and the human gut: New beginning of an old story". World Journal of Gastroenterology. 20 (43): 16062–16078. doi:10.3748/wjg.v20.i43.16062. ISSN 1007-9327. PMC 4239492. PMID 25473158.
9. Kiverdi: about