Cultured meat is made from animal cells that grow in large laboratories instead of animals. The goal is to make products that are virtually identical to normal animal meat without the entire animal. On the other hand, single cell protein grows microbes (bacteria, fungi or algae) and harvests them to generate protein rich product, which can be eaten or processed further. This post is about some important differences between both and why I am more excited about single cell protein, although cultured meat has some advantages.
The Single Cell Protein Process is Simple
Bacteria and other single-celled organisms always try to grow and divide. That is how their genetic material survives. They do not care whether they do so in a bioreactor, water or soil. Cultured meat on the other hand strives to grow muscle tissue. Muscle tissue grows during development but then it stops. In adults, muscle tissue only grows under very specific conditions (ask bodybuilders). Therefore, cultured meat requires very specific signaling molecules called growth factors.
Cultured Meat Requires Growth Factors
Growth factors are arguably cultured meat’s biggest challenge. They are the most expensive part of the production process and they are also not exactly appetizing. Growth factors for laboratory use are produced from fetal bovine serum, which in turn is extracted from the blood of fetal cows. During early development cows have a lot of muscle to grow so their blood serum contains many important growth factors. This makes many current cultured meat products non-vegan. Growth factors also make up a large part of the high price. Efforts to create plant-based serum are ongoing but reaching the efficiency of the fetal bovine serum has been challenging.
Cultured Meat Scaffolds
Another complicating factor is that muscle cells are not used to growing suspended in fluids. Especially when the goal is to make products with consistencies and structure similar to real meat, special structures called scaffolds are required. Scaffolds can be an edible part of the product or they can require removal during processing. They can be from animals or plant-based. Either way they add to the complexity and the price tag of the product. Single-celled organisms on the other hand do not require growth factors or scaffolds. Besides their simplicity, single-celled organisms have the key advantages that they can get their energy efficiently from many different sources.
Single Cells Can Use Many Simple Energy Sources
Muscle cells primarily get their energy from sugar. Sugars can be produced by plants, which are the traditional backbone of food production. Single-celled organisms on the other hand are much more diverse, which is a massive advantage for single cell protein. There are organisms that can eat fossil gas, oil or single carbon compounds such as methanol. Methanol can be made from hydrogen and captured carbon dioxide. Some organisms can even use hydrogen and carbon dioxide directly.
Hydrogen in turn can be made from electricity and water. Plants get their energy from the sun and we can also use the sun to feed microbes with the efficiency of photovoltaics. But it gets even better: electricity can be generated from the sun, wind, hydropower, tidal forces, geothermal or nuclear. Therefore, single cell protein liberates traditional food production from its single solar energy source. This massively expands the possibilities of food production and could make it unthinkably efficient.
This is in my opinion the most crucial advantage of single cell foods. However, since I have so far primarily highlighted advantages, I also want to highlight one of the important challenges of single cell protein: nucleic acid concentration.
Single Cell Protein Nucleic Acid Concentration
Nucleic acids are the building block of every organisms genetic material, including humans. They are also essential for the translation of genetic material into protein. They are found in all natural foods. Ingested at high concentrations they are associated with kidney stones and some other health issues in humans. Some single cell protein products can have very high nucleic acid content but it varies widely between the specific organism. Nucleic acid concentration is not an issue with algae.
For organisms with high nucleic acid concentrations, an extra processing step is necessary, where the concentration is reduced. For example, enzymes called RNAses can be used to break down nucleic acids. As the first single cell protein products are approved for human consumption, it will be interesting to see how companies deal with nucleic acid concentration. The simplicity of the single cell protein process works to its advantage during production. However, the complexity of cultured meat can result in more interesting products.
Cultured Meat Products are More Varied
While the complexity of the production processes is a detriment, the resulting variety of products is an advantage of cultured meat. Cultured meat products can imitate different meat cuts or different species (beef, pork, poultry). As described above, this is extremely difficult and is still impossible to do in an affordable way.
The initial product of single cell protein on the other hand is most of the time some kind of protein rich powder. These powders differ in protein content, their exact amino acid composition and bioavailability. They can then be processed further into a tofu-like product or can be used as an ingredient in different foods such as pasta, ice-cream or anything else where you would like protein. This way, single cell protein products can also end up in diverse products, although the initial protein powder is always the same. Generally, because of their structural differences both appeal to different markets, where they have different challenges.
The Cultured Meat Market
Cultured meat is targeted primarily at people that value the taste and texture of meat. The value proposition is that cultured meat provides that taste with less environmental destruction and without killing animals. A central issue is that people who consume a lot of meat, by definition do not care enough about these issues to reduce their meat consumption. Some people care. Their only barrier is that they cannot give up the taste of meat and they will be willing to pay a premium to get that.
Most people will not. That means cultured meat will need price parity with traditional meat. Given the complexity of cultured meat, this is a massive challenge. I consider it extremely unlikely by 2030 and even 2040 but the cultured meat industry is more optimistic. Of course there is also a market before price parity and people already on plant-based diets might include some amount of cultured meat in their diet as well. Single cell protein faces a different challenge.
The Single Cell Protein Market
Single cell protein does not specifically target meat eaters. As a standalone product it attempts to imitate tofu rather than meat and as an ingredient it replaces egg and dairy. Many people who are interested in replacing meat/dairy/egg in their diet have already done so with plant-based products. Plants are natural and healthy and I expect few people will eagerly switch to single cell protein, despite its environmental advantages. Algae and fungi might have some minor advantage over bacteria here, because they are more similar to plants. Acceptance of novel foods is overall low and both cultured meat and single cell protein will face challenges. Even with optimized processes and products, adoption will take time.
Summary
Cultured meat and single cell protein will both face challenges, some similar, others different. I believe the technical challenges of single cell protein are easier to overcome and its environmental advantages will be greater than those of cultured meat. Novel food acceptance will be similarly problematic for both and depending on the market different products will have slight advantages. Both will hopefully do their part to reduce the environmental impact of food production.
Further Reading
Cultured Meat Review:
Broucke, K., van Pamel, E., van Coillie, E., Herman, L., & van Royen, G. (2023). Cultured meat and challenges ahead: A review on nutritional, technofunctional and sensorial properties, safety and legislation. In Meat Science (Vol. 195). Elsevier Ltd. https://doi.org/10.1016/j.meatsci.2022.109006
Single Cell Protein Review:
Ritala, A., Häkkinen, S. T., Toivari, M., & Wiebe, M. G. (2017). Single cell protein-state-of-the-art, industrial landscape and patents 2001-2016. In Frontiers in Microbiology (Vol. 8, Issue OCT). Frontiers Media S.A. https://doi.org/10.3389/fmicb.2017.02009
Title image generated with Stable Diffusion.