Making Milk from Yeast — Acellular Agriculture Revolutionizing the Dairy Industry
With an ever-growing population, our dependency on resources such as food, water, and nutrition has been alarmingly increasing across the globe. Indeed, the drive for manufacturers to deliver they must contend with an age-old dichotomy: how to accelerate and improve product quality while driving down costs and diminishing negative impact on the environment.
Within this difficulty lies animal agriculture, which poses additional threats to our planet. Considering how farm livestock produces more greenhouse gases each year than cars and vans put together, 25% of the earth is for farming livestock, 70% of all land is designated for agriculture, 18+ refrigerators of drinking water could be preserved if we all just took one less sip of milk in our bowls of cereal, and cows are only 3% effective in converting nutrients fed to them into milk, something needs to change.
Clearly, it’s not just cows emitting methane that contributes to the issue of our lifetime, or the livestock transmitting e-coli to humans. It’s beyond just CH4 and e-coli. To solve our biggest problems, we’re going to have to leverage science and innovating technologies of the 21st century, and fast.
Introducing cellular agriculture.
Cellular agriculture is the production of animal-sourced foods from cell culture.
Cellular agriculture is a bio technique that builds off of cell culture for the production of animal-sourced foods.
Cellular Agriculture: The use of stem cells, tissue engineering, fermentation, and gene editing to culture cells into real products — anything from muscle tissues, to material products like leather.
There are two types of agricultural products derived from cell cultures: acellular products and cellular products. Acellular products are composed of organic molecules such as proteins and fats, but no cellular or living material is present in the final product. On the other hand, cellular products are composed of living or once-living cells.
Products harvested from cell culture are identical to those harvested from an animal or plant — the only difference is how they are made.
So, cellular agriculture is based primarily on the concept of the cell. Recently, I’ve been super interested in the future of food so this article is going to be an “in a nutshell” of everything you need to know about cellular agriculture for producing milk.
The reality of cows held together in tight rows, chained down into tie-stall barns is true for millions of cows. And once their calves reach a healthy diet for their age, they no longer need milk as cows produce it. Therefore, humans. collect this excess milk for consumption. Once cows are milked, more milk is quickly replenished and needs to be milked again — starting a cycle of unhealthy and cruel product development.
Now, milking cows is a good thing and dairy is great. But it’s not about milking cows, it’s about how we’re doing it.
The global dairy market is valued at around $725 Billion and is expected to reach $950 billion in 2025. Every decade, dairy products grow by 18% in their carbon footprint, while average cow herds scale up by 11%. And every year, milk yield increases by 15% and total dairy greenhouse gas (GHG) emissions reach a project 38% increase in the same timeframe.
All of this destruction to our environment for one of the most inefficient technologies in the world. No one would accept a technology that’s only 3% effective. To put it in perspective, for every 100 kg of nutrients fed to a cow, a mere 3 kg is given back. So, although cows can produce milk, they’re not built to do at a commercial scale — yet we still must deal with the tons of GHGs being pumped into our atmosphere by the dairy sector. And without proper sustainable development innovations, these numbers are only expected to rise, clearly something we are not prepared for.
Compared to the emission intensities of non-dairy products, dairy generates 35X more greenhouse gases. For instance, the cheese ratio to GHG is 5.9 kg of CO2-Eq/kg, whereas peanut butter is a mere 0.17 kg of CO2-Eq/kg. That’s crazy how the associated GHG emissions of dairy products are 35 times greater than other products.
Using the zero-grazing method, cows are kept restrained from pastures — introducing them to an array of welfare issues and abuse. Cows become weak as their hooves swell from laminitis, or as they suffer mastitis, an udder infection that is responsible for 16.5% of all cow deaths. Additionally, over 13% of cows in the US become infertile, stopping them from completing their evolutionary function of reproduction.
With zero-grazing, a majority of cows are kept confined in tie-stall barns. The flooring leaves their hooves to suffer extreme bone and muscle damages, increasing the rate of lameness. The cows are also subjected to a high risk of infection and disease transmission — a devastating reality for over 40% of cows.
We’re also injecting cows with a bunch of growth hormone treatments, and in the process, increasing the associated risks with dairy product consumption which stimulates unnatural responses within the human body. One such example is the recombinant bovine growth hormone or somatotropin (rBGH/rBST) — a growth hormone acquired from the somatotrophin hormone present in the pituitary gland — which is a factor that promotes growth and cell replication.
The rBST is engineered through editing the somatotrophin gene to create a hormone that promotes growth within cows. However, the rBST hormone has been under scrutiny, as available evidence shows that the use of rBGH can cause adverse health effects in cows. Concentrations of insulin-like growth factor 1 (IGF-1) — a substance in high enough concentrations that can inadvertently promote the development of tumors in the body — have been found to be present in the hormones. Overconsumption of milk specifically from bovines who were treated with these growth hormones can lead to higher levels of prostate, breast, and colorectal cancers. Our traditional methods of producing milk are detrimental to the health of cows, as well as to humans.
The cows are experiencing a genocide, but there’s a really simple solution.
Milk isn’t a super complex substance— it’s just water, proteins, and nutrients. So instead of using a 2000lb cow to produce our beloved dairy proteins, we can use genetically modified yeast to produce identical proteins (all from a lab, too).
In simple terms, traditional cow milk technology starts with impregnating cows. Once the calf is born, it is taken from its mother, and the mother cow is then connected to several machines. This marks the start of the milking process which spans roughly about 1 year. The cow is then impregnated again, and the process continues.
However, instead of keeping mother cows in a lactating state in industrial settings, we can make the same exact milk by brewing it, using genetically modified yeast that consumes simple sugars to make milk proteins. Once we have the proteins, all that’s left is to mix in water and nutrients and we are left with the milk identical to that of a cow.
You might not have realized it, but you already have an idea of how yeast works. When you feed sugar to a baker’s yeast, it produces CO2 that makes the bread rise. Or when you feed sugar to brewer’s yeast, it produces alcohol. This happens not only because of the yeast, but because of a process called fermentation — we’ll get to that in a second.
Anyway, yeast is a member of the fungus kingdom that is the key to acellular agriculture. Remember that acellular agriculture is just a subtype of cellular agriculture where cells or microbes — yeast in this case — is used not to form the basis of the products themselves but rather as a “factory” to produce fats and/or proteins (like milk). Unlike meat or leather, acellular agriculture products contain no cellular or living material.
But let’s go over how this is done- First, we’re going to have to talk about a key process: fermentation.
Fermentation 101
Fermentation is one of the oldest natural processes to be harnessed for food production — giving us traditional fermented foods and drinks like bread, alcohol, yogurt, kimchi, miso, beer, wine, and some pickled foods. Fermentation is key to everything under the acellular agriculture umbrella as well.
From a biological standpoint, the definition of fermentation is pretty narrow, referring to a microorganism’s metabolic pathway for converting food into energy in an environment without the presence of oxygen. However, food makers have borrowed this scientific process to bring about desirable changes in entire foods too.
Currently, there are three main ways food makers utilize the fermentation process. Traditional fermentation has been used for millennia to transform food, and biomass fermentation is another method that’s been used for over a century.
The method cellular agriculture companies are harnessing is more recent — precision fermentation. This innovative technique enables food makers to develop super specific, highly pure ingredients, unlike what’s produced from traditional agriculture processes. In the case of creating nutritious, functional, and versatile dairy products, microorganisms convert sugars into whey and casein, the vital dairy proteins that make milk, milk.
But to truly understand the new, precision fermentation process, it’s helpful to first know how traditional and biomass fermentation work too:
- Traditional fermentation has been used for thousands of years and was likely discovered accidentally when humans noticed how their food changed under certain conditions.
Imagine you’re back in early nomadic times. Herd animals have been recently domesticated for their meat and milk. After completing your morning milking of the cow, you decide to store the milk inside a pouch made from an animal’s stomach. You carry this pouch with you as you travel throughout the day. When you finally open the animal skin pouch, the milk has changed — it’s thicker and a tad bit sour. Unbeknownst to you, extremely tiny, invisible organisms present inside the pouch have been fermenting the milk into an almost yogurt-like substance.
In traditional fermentation, agricultural products such as legumes, grains, milk, and even meat are inoculated with live microorganisms in order to transform those products. However, early nomads could not have realized that this transformation was due to the microorganisms present. Eventually, over time, humans figured out how to produce the right conditions for it to take place. And to this day, fermentation has been used to influence the flavor and texture of foods and prevent spoilage. We also use traditional fermentation to improve nutrition and bioavailability — the ease with which food or a nutrient is digested by our bodies. - Biomass fermentation is a similar process to traditional fermentation, however, the final, edible product is the microflora itself. In biomass fermentation, fungi or bacteria are introduced to a substrate — the microorganism’s food source — on which they eat, grow, and reproduce. This process takes advantage of the microflora’s ability to reproduce exponentially. Raising livestock or growing crops can take anywhere from a few months to years, while microflora populations can double in a couple of hours or even minutes. This results in a mass of cells — also called the biomass —which is very high in protein and fiber and useful in flavor additives, meat substitutes, and a growing segment of the alternative protein industry.
- Precision fermentation combines microorganisms’ natural ability to transform sugars into other materials with modern tools of biology to create useful products. In other words, precision fermentation makes high-value products from lower-value ones in nature. Especially capitalizing on today's modern biological tools, equipment, and understanding of genetics, scientists can co-opt microflora’s natural inclination to make energy — repurposing it to produce almost any complex organic molecule.
Now that you have an understanding of the different types of fermentation, let’s get into how we get the microflora in the first place — in this case, the microflora is yeast.
Like I said before, milk is not very complex:
That’s all it is.
We can easily get water and nutrients, so how do we get the proteins? Well, the main proteins found inside milk are casein and whey. These high-quality proteins are in about an 80 to 20 percent ratio and are composed of extremely essential amino acids — in high quantities.
So if milk is composed of such simple products, couldn’t we recreate it in a lab?
That’s right, we could.
And that’s where cellular agriculture comes in, again.
The Process: Genetically Modified Yeast
And it all starts with genetically modifying yeast.
The goal of this is to alter the yeast’s DNA so that it possesses the same protein-producing genes that cows contain. In turn, this will enable the yeast to produce the same exact proteins cows do.
First, we must introduce those protein-producing genes to the yeast cells in a universal code: DNA. Essentially, this gives the yeast cells the cow’s “recipe” of how to make milk proteins. But we don’t want just one of the yeast cells to contain the introduced DNA, so the cell must replicate with the new gene sequence many times. Therefore, if the original cell is destroyed, we’ll have numerous copies or clones of that yeast cell.
The genetic engineering process is completed through a plasmid — circular bundles of DNA — of a yeast cell. The plasmid replicates indefinitely — a process also known as cloning — in order to transfer genetic information to other parts of the cell. It’s important to note that the plasmids exist in addition to the yeast cell’s chromosomes, meaning that when the plasmids are extracted the cells are still able to function. During this process of genetic engineering, the plasmid is in fact extracted and gene-edited. As seen in the figure above, the DNA inside the plasmid is cut, the DNA sequence from the cow is inserted, and then the plasmid is introduced into the yeast.
The DNA pieces produce recombinant DNA, which is DNA composed of fragments from different sources — in this case, it’s from cows and yeast.
When the recombinant DNA is introduced into yeast cells, a process known as genetic transformation, the new genetic information is transferred into the chromosomes of yeast cells, and they begin dividing — producing the desired casein and whey proteins.
Now, we have some sustainable lab-grown yeast. However, if 700 million liters of milk are consumed every day (not including any dairy byproducts), then we must be able to produce proteins at a level that sustains our global population.
That’s where the process of fermentation comes in.
Fermentation at Scale
A bioreactor — also called a fermentation tank — gives the perfect environment needed by the yeast to flourish. Think back to the milk curdling inside that animal-skin pouch. Given the microorganisms, right temperature, the right level of agitation, and the right feedstock, the milk was able to turn into yogurt. Inside the bioreactor, the same thing happens, as it provides the yeast with the perfect conditions for producing a lot of protein.
First a growth media — a nutritious liquid containing plant-based sugars microflora thrive on — is added to a sterile bioreactor containing water, oxygen, nitrogen, salts, minerals, and vitamins. Next, the growth media mix is inoculated with the microflora in a controlled environment. The perfect adjustment of the temperature, pressure, pH and stirring action inside the bioreactor enables the microorganisms to effectively eat, grow, and multiply. As the flora consume sugar and reproduce exponentially, copious amounts of desired proteins are pumped out.
Once all the sugar is consumed and the microflora halts their multiplication, the fermentation process terminates. The broth — containing water, microflora, protein, and leftover growth media — is drained from the bioreactor. Then purification occurs where the produced protein is separated from the microflora, filtered, purified, and finally dried; leaving an end product of extremely pure protein powder ready for use by food makers.
The casein and whey are then packaged, ready to be shipped out to produce dairy byproducts like ice cream, cheese, yogurt, and more.
Specifically for milk, we mix the proteins from the bioreactors with the other milk components, like glucose + galactose sugars (lactose) and water. From there, we can take the milk and convert it to anything.
3D bioprinting Cow DNA
To actually genetically modify the yeast, we 3D print the specific genetic sequence of a cow and then insert it in the plasmid of the yeast cell. We know that once we have the plasmid, it’s introduced to the rest of the yeast cell; however, 3D printing is very expensive. A single 3D printer costs anywhere from $10,000 to $900,000. That’s a lot of money, and these animal-free dairy products won’t be able to disrupt the industry until it’s actually affordable.
We already have the identical tasting alternative, we just need it at a comparable market price — something we still have left to solve.
If you think about it, brewing dairy requires quite a lot of resources. First, it requires 3D printed cow gene protein sequences so plasmids of yeast cells can be genetically engineered to contain those genes. Then the process requires us to cut the plasmid’s DNA and enter the cow genes. Next, we must place the yeast in bioreactor tanks where it is fed nutrients and sugars for growth. Finally, the proteins produced must be purified and developed into the foods we enjoy.
The process is expensive. But if we scale up the process then more dairy production factories have it, and the cheaper it will become to produce the dairy.
We shouldn’t be wasting 97% of the nutrients we feed cows, wasting water, land, energy, and our precious resources. But, we should be using a yeast-based process instead of an unsustainable and cruel dairy production system that endangers both cows and our own health.
And there are already possible solutions to the challenges presented with this new, innovative method.
Utilizing the Internet of Things to improve the process
Technologies aren’t perfect, and using yeast to create dairy is no different. However, to ensure that this technology will revolutionize the dairy industry as we know it we must utilize other innovative technologies. One such technology is the Internet of Things (IoT) based bioreactors — or the integration of interconnected sensors that monitor breweries.
IoT technology will have a groundbreaking impact on how yeast is fermented, especially given that one of the most difficult aspects of the process is monitoring the protein production occurring within the bioreactor tanks. Currently, companies are relying on human labor to manually monitor the tanks — an unpractical expense filled with inaccuracy and error.
However, with an IoT network of bioreactors there are many benefits:
- Lower maintenance
- Cut on production and management costs
- More observation of yeast cell behavior and how yeast cells grow
- Accurate milk brewery diagnostics and analysis of conditions
- Monitorization of protein conversion rates, nutrient intake, and various factors that could optimize the production process
- Create cheaper yeast-protein production
Overall, fermenting dairy proteins through yeast cell cultures will transform the dairy industry as we know it. There’s some really cool stuff happening within the cellular agriculture field.
The process isn’t perfect — at least not yet. But we’re getting there and the implications will be far greater than imagined.
If you enjoyed this article make sure to clap it and follow me!
Also, find me on LinkedIn!! And if you want to join my journey subscribe to my month newsletter HERE.
If you want to check out some really cool companies working on this, look 👇
