Single-Cell Protein

Single-cell proteins (SCP), sometimes called microbial proteins, are edible unicelular microorganisms containing high amounts of protein. These can be farmed using biomass fermentation:

Biomass fermentation

Biomass fermentation is where the whole microbe (or a dried version) is the product of fermentation.

Given the relative ease of downstream processing when the whole microbe is used, and their gastronomic potential, biomass fermentation may be the preferred route for open source fermentation.

Most types of living microbe could potentially be used for biomass fermentation. We’ll break these down into fungi (yeasts and moulds), bacteria and algae:

Fungi

Fusarium venenatum

Quorn mycoprotein is a well known proprietary product of biomass fermentation. It uses Fusarium venenatum, a filamentous fungi. Quorn’s original patents expired in 2010 but their £30M fermentation towers may prove challenging for open source development.

Sustainable Bioproducts, Inc and 3F Bio Ltd have also submitted Fusarium venenatum GRAS (Generally Recognised As Safe) notices to the US-FDA.

Harrison Lab have published bioinformatic analysis of Fusarium venenatum genomes on GitHub.

Bacteria

Xanthobacter spp.

While we, and (many)[https://www.penguin.co.uk/books/317018/regenesis-by-monbiot-george/9780141992990] (others)[(https://theses.hal.science/tel-03718434/document)] previously reported that Solar Foods use Cupriavidus necator to produce their proprietary Solein largely from air, their EU Novel Food application indicates that they are using a Xanthobacter species.

Solar Foods take carbon dioxide and water vapour from air. They use solar powered hydrolysis to split the water, providing hydrogen which C. necator can use as its energy source. Ammonia is used as the nitrogen source. https://food.ec.europa.eu/system/files/2023-08/novel-food_sum_ongoing-app_2021-1730.pdf

Cupriavidus necator

Novo-Nutrients and Kiverdi are thought to use Cupriavidus necator.

Algae

Through photosynthesis, algae use sunlight to produce sugar and oxygen from carbon dioxide and water. Nitrogen can be metabolised from urea, meaning all major feedstocks are freely available.

As such (and since a number of algae, containing all essential amino acids, are already sold as ‘superfoods’ for human consumption) algal protein may be the quickest win. That said, it may not be as gastronomically appealing as other proteins on our shortlist.

Arthrospira platensis

Spirulina is commonly used as a food supplement, but Spirulina Gnocchi has been proposed by the European Space Agency for Mars Missions. It has a slightly sweet nutty taste. Spirulina is technically a cyanobateria rather than algae, which means the risk of cyanotoxins (e.g. microcystin, alkaloids and BMAA) need to be mitigated.

Chlorella

Chlorella arguably tastes worse than Spirulina. They also have a lower protein concentration and cellulose walls. In their favour: they are single celled, so may be easier to process, and should not produce cyanotoxins.