Today’s agricultural production has an enormous impact on our planet; about one third of global greenhouse gas emissions are linked to our food system, about half of the planet’s habitual land is occupied by agriculture — 77% of which just livestock production— and about 70% of global water withdraws are for agricultural purposes. If that was not enough, intensely managed agricultural systems often rely heavily on the inputs of pesticides, herbicides, and fertilizers to suppress the natural process of species diversification on the land and leading to problems like eutrophication and soil exhausting. This all has greatly contributed to the decline of our world’s biodiversity. Did you know, for example, that 94% of all the mammalian biomass on earth today is made up by livestock. Although we produce enough food to feed all, many millions go hungry every day.
The consequences of current food production for the environment have never been so pronounced in human history, threatening the relatively stable state in which the Earth system has remained over the past 11,700 years of the Holocene epoch. Yet, the Food and Agriculture organization (FAO), estimated that by 2050 we would need to produce 60% more food to feed the estimated 9.3 billion people that will inhabit this planet by then. This means that the agricultural sector will likely increase the pressure it puts on our planet unless we radically change the way we produce our food.
In search for sustainable protein alternatives: Cellular agriculture
In the quest to reduce the environmental impact of the food system, the search for more sustainable protein alternatives to replace animal-based proteins is one of the foremost research topics in food science and biotechnology today. Cellular agriculture is an approach that decouples food production from conventional agriculture and animal farming and therefore has the potential to decrease the environmental burden associated with food production. Cellular agriculture is the production of agricultural products using cell-culturing technologies. Perhaps the most commonly known example of a cellular agriculture product is that of cultured meat (also known as in vitro, cultivated or cell-based meat), where muscle cells are grown in a bioreactor with the help of tissue engineering technologies.
Cellular agricultural products are divided into 2 groups: acellular products and cellular products. Cellular products are those that contain living or once-living cells while acellular products do not. Cultured meat (also known as in vitro, cultivated or cell-based meat) is perhaps the most well-known example of a cellular product. Another example is microbial protein, a single-cell protein powder produced by hydrogen-oxidizing bacteria. These bacteria require hydrogen, oxygen, and CO2 gases during the fermentation process as well as ammonia and other minerals (sulfur, phosphorus, iron etc). The bacteria and nutrients are pasteurized, separated from liquid, and dried into a flour-like protein-rich powder with a 65% protein content. This powder can be added to food ingredients, such as plant-based patties, pancakes, or smoothies to boost the protein content. Alternatively, it can be fed to livestock as a replacement of other protein sources, such as soybeans that are often link to deforestation of rainforests.
Examples of acellular products are casein (comprising about 80% of the protein in cow’s milk), gelatine and ovalbumin. Ovalbumin is the dominant protein found in chicken-based egg white — about 50%. Ovalbumin is produced using a fungus called Trichoderma reesei. The gene that carries the blueprint for ovalbumin is inserted into the fungus that then starts to excrete the targeted ovalbumin. The production takes place in a bioreactor where the T. reesei fungi is fed with glucose that is supplemented with a number of micronutrients. Unlike with the microbial protein, the fungi are separated from the produced protein, meaning that the final product only contains the targeted ovalbumin. Also here, the final product is a protein powder with a protein content of 92% and can directly replace the chicken-based alternative in the food sector.
Although these technologies sound futuristic, cell-culturing technologies have been long around. For example, the vast majority of insulin is produced through cell-culturing technologies, replacing animal-based insulin from the pancreases of pigs or cattle. Cell-cultured insulin is made by inserting the gene that carries the DNA of human insulin into a bacteria that then starts producing the product. The benefit of this process is that the production process can be fully controlled and is identical to the insulin produced by humans themselves. Also examples of plant-based cellular agricultural products exist. Vanillin, the main component that gives vanilla its flavour, is with cell-cultured by a Swiss company using yeast.
Animal-based food replacements produced with cellular-technologies have the benefit of being made based on the animal-cells and therefore have the many of the same properties as the those produced through livestock production. They, therefore, differ from plant-based alternatives. For example, ovalbumin made with fungi has shown to have the same (or even better) foaming properties as that of chicken-based egg white. The fact that these products can contain actual animal-based cells might also have the potential to persuade those that are not convinced by the plant-based protein alternatives.
Are cellular products an environmentally friendlier option to animal-based protein sources?
More and more research is coming out to investigate the environmental impact of these novel cellular agricultural protein sources. Recent work has shown that, indeed, there is potential for these products to lower the environmental impacts related to protein production. This is especially true when cellular agricultural products replace animal-based protein sources, such as meat, milk or eggs. Reductions in the environmental impacts were largely related to the reduced amount of land that is needed to produce the protein. For example, when producing ovalbumin with T. reesei instead of chickens, land use requirements were about 8.5 times smaller while global warming potential was about half. Microbial protein had even lower environmental impacts than ovalbumin production with fungi. Environmental impacts of the cellular agricultural products could be even further reduced when renewable energy sources were used in the production processes. This is because cellular agricultural products are produced within an industrial setting, rather than on agricultural land and most environmental impacts are therefore associated with the use of industrial energy.
This is especially true for microbial protein that is completely decoupled from any agricultural inputs. This means that its production process is not associated with many of the typical environmental impacts associated with agricultural production, the use of pesticides and the leaching of nutrients into water bodies leading to eutrophication. Another benefit of the independence of agricultural land, is that microbial protein can be produced anywhere in the world, in principle. It does not require fertile soils to grow, unlike agricultural products. A strategic location for its production would therefore be one that generally has a low agricultural potential, to reduce the pressure that the food system places on the limited land our planet has.
In general, the low land requirements of these cellular agricultural products also means that in case that animal-based protein sources are replaced, agricultural land would be “freed” and could be used to restore ecosystems, helping both in the sequestration of carbon from the air and restoring biodiversity.
As for cultured meat, the environmental benefits at this point are less profound. Conclusions depend a lot upon the choices within the production process and the potential use of renewable energy. While cultured meat has proven to show a potential to lower environmental impacts in comparison to beef production —especially in terms of global warming potential and the use of land — the choice for poultry meat still results in lower environmental burdens in comparison.
While it might be a while before we see cultured meat in the stores here in Europe, cell-cultured meat is currently only available in Singapore for a limited market. Also Solar Foods, a company that produces microbial protein, has recently received approval from the Singapore Food agency. Companies that are developing and producing microbial protein, ovalbumin and casein production through cellular agricultural technologies are currently working to become commercially available within USA and/or Europe.