From Yeast to Milk — Acellular Agriculture at Its Finest.

Kavya Mulgund
7 min readJan 30, 2021

MILK.

The liquid necessary for growth. The liquid that babies cry for. The liquid that pairs so well with cookies, that eating cookies without milk feels like a crime!

Yes, milk is elite.

But not at the cost of cows and other milk producing animals. There are nearly 8 billion people on this planet and close to 6 billion of them consume milk. Cows are forced into a harsh cycle of milking, which eventually leads to their death. I find that absurd and saddening.

What if I told you that there was a way to produce milk and other dairy products without harming cows?

Introducing cellular agriculture

You might be wondering, what exactly is that? Well, simply put, cellular agriculture is the technology and the science behind producing products without the use of animals. There are 2 types of cellular agriculture products. Cellular and acellular. Today, I will be focusing on the latter.

If you want to learn more about cellular production, click here!

Acellular products refers to things such as casein, omega-3 fatty acids, vanillin and gelatin. These products are made from molecules like proteins and fats, and contain no living material or once-living cells (unlike cellular products).

For the purpose of milk production using yeast, I will be focusing on 2 very important proteins. Whey and casein.

Whey and casein are the proteins in milk that are responsible for making it such a creamy, silky and delicious thing to chug!!!

The components of cow’s milk

Cow’s milk is made up of 6 primary proteins. 4 being casein, and 2 being whey. Two significant caseins are called beta-casein and kappa-casein. While the 2 wheys are called beta-lactoglobulin and alpha‐lactalbumin. Casein is a major source of nutrients including amino-acids, calcium and phosphate. While BLG(beta-lactoglobulin) transports retinol in the milk and aids in the digestion of lipids.

The more you know, am I right?!

Note: For the sake simplicity, I will be calling these proteins just whey and casein.

Without further ado, let’s jump into the process of making milk without actually milking a cow.

The Process.

  1. Use a microbe → Yeast or bacteria will do
  2. Insert gene into microbe
  3. Fermentation
  4. Purification
  5. Final Product

Now for the sciency details…

#1 Use a microbe

Using a microbe is the reason that this process works. By choosing yeast as our host, the cells will be able to replicate and thus produce the necessary proteins.

Why yeast?

The reason that yeast is used is that it’s a eukaryote — meaning that it contains the complex organelles that are found in animal cells. Yeast is able to conduct PTM (post-translational modification) which means that it is can form mature protein products, which in our case will be casein and whey! Not to mention, yeast allows for rapid growth.

#2 Insert a gene

Here’s where it gets a little tricky. Before we dive in, here’s some terminology.

  1. Plasmid → Circular piece of genetic material that is separated from the chromosomal DNA of the cell. It can be found in bacteria and eukaryotes.
  2. Host cell → The host is the cell that is being manipulated, meaning it is a living cell that can be invaded by a bacterium, gene or even virus. In this case, it’s yeast.
  3. Recombinant DNA → rDNA is DNA that was made possible due to genetic engineering or work done in a lab. That DNA would not be found in the genome if it was’t played around with!

Okay, this sounds more like gene editing than cellular agriculture😲.

That’s the beauty of cellular agriculture! It’s truly an encompassment of several different technologies.

In order to insert the gene into the yeast, scientists use a plasmid of the yeast cells. Plasmids are able to contain the gene that is taken from the cow. The gene from the cow is the gene that contains the instructions for the creation of these two proteins.

Because of the advancements in the DNA synthesis, the donor(the animal) isn’t even required! People can find the DNA sequences of the cow genes on free databases, and manufacture the DNA in labs — the science of genetic engineering.

Once you have the gene, a section of the plasmid is cut and the cow gene is attached to the plasmid. This results in rDNA.

gene + plasmid → rDNA → inserted into yeast

Then, the recombinant DNA is inserted into the yeast meaning that the genetic information is transferred to the chromosomes of the yeast cells. Now the yeast can act as the cow, thus producing the proteins!

#3 Fermentation

To ensure that that casein and whey are being produced, scientists are using a process called fermentation.

According to the Good Food Institute, fermentation means “any controlled large-scale cultivation of selected microorganisms or cells for the production of desired product[,] this product can be a protein”.

The vessel used for the fermentation is called a bioreactor or fermenter.
A bioreactor is essentially a large tank that houses the cells in a controlled environment with nutrients for growth and replication. Since the cells are in a suitable environment, this allows for division and replication, which in turn result in more proteins being made. For dairy production, bioreactors are also used to make sure that the yeast converts the sugars and nutrients(supplied by the bioreactor) into the necessary proteins(whey + casein).

The Old way vs the New way
Sugar and yeast are involved in fermentation to make the milk proteins

#4 Purification

The process is almost done. Since the yeast converted the sugar into the proteins(the process of fermentation), the proteins need be isolated from the genetically modified yeast. So, the protein is separated from the host cells and purified. Now the proteins are ready to be incorporated with other substances to reach the final product.

#5 Final Product

Yay! Now that we have the whey and casein, companies are able to use these proteins to create different dairy products.

Note: By using the method of fermentation, where sugars convert into proteins, the resulting protein does not HAVE to be casein and whey. They could be different proteins depending on the genes that are inserted.

Perfect Day — Founded by 2 Vegan Dudes

Pandya(left), Gandhi(right)

Perfect Day. Sounds good to me!

Well, it’s actually a startup company based in California. It was founded by Ryan Pandya and Perumal Gandhi. Both Pandya and Gandhi were motivated to find a way to make dairy products in a more sustainable and humane way that tasted just like regular dairy products. The process involves many of the ideas covered above. But, the interesting thing is that they didn’t stop at milk! Perfect Day is producing cheese, yogurt, ice cream and milk all using cellular agricultural technology. Their process goes something like this:

  1. Use microflora → Perfect Day uses fungi
  2. Insert gene into microflora → the gene contains the genetic ‘blueprint’ for the desired protein.
  3. Fermentation process (they grow their flora in large tanks at the optimal temperature, pH, and salinity)
  4. Produces pure protein → does not contain lactose, cholesterol, hormones etc.. that would typically be found in cows milk.
  5. Proteins become cheese, yogurt, ice cream and other dairy products
A picture of Perfect Day’s products, including milk and cheese.
Animal Free Milk and Cheese

Now that I’ve talked about the science behind this super cool milk! Let’s talk advantages and challenges.

Why choose this milk over cow’s milk?

If by 2050, there are going to be 10 billion people on this planet, imagine the amount of milk that cow’s in factory farms are going to need to produce in order to keep up with our growing demands! Cow’s milk just isn’t sustainable. We need a solution, and that’s where animal-free milk comes in.

Environmental Impact

The shift to yeast made milk could result in a 98% decrease of water consumption and 65% less greenhouse gas emissions.

As a matter of fact, Perfect Day found that its milk uses around 77-­91% less land, and has 35­-65% lower emissions.

More advantages

  1. Longer shelf life for milk because there are no animal products in it
  2. Fetal bovine serum(refined cow blood) is not used
  3. No need for cows to be kept in unsuitable environments
  4. Better for the environment

Challenges

  • Public Perception. There are many people who are still wary about animal-free products. Is it safe? Is it actually whey and casein? Does it taste good?
  • If animal-free milk becomes popular, this could lead to a decrease in dairy farmer’s jobs
  • Scalability. The use of bioreactors/fermentation, purification and genetic engineering is costly, but with more startups looking to produce animal-free products, this will change!

That’s about it!🐮

The science behind making products without animals has been here for 40 years, but the world is finally realizing it’s potential! I find this technology super fascinating and can’t wait to try animal-free milk.

Thank you for reading! My name is Kavya and I have recently been learning more about cellular agriculture. If you would like to join me on my journey of learning and growing, you can subscribe to my newsletter here.

Feel free to contact me through LinkedIn, or email me at kavya.mm@gmail.com.

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Kavya Mulgund

19y/o cellular agriculture enthusiast. Learning, writing, growing!