Genetically Modifying Yeast — Changing The Future of Dairy

Isabella Grandic
7 min readNov 15, 2018

If cows were considered a technology that created milk, they’d be 3% effective in converting nutrients. That’s a really inefficient technology and nowhere in the world would that technology be excepted. Milk isn’t super complex — it’s just water, proteins and other nutrients, we should be able to make this in a lab.

Instead of using a 2000lb cow to produce dairy proteins, we can use GM yeast (genetically modified yeast) to produce the exact same proteins that are necessary for the production of dairy in labs.

Once we have the proteins, we mix in water and nutrients and boom we have milk.

To be put it in the simplest of terms, normal cow milk “technology” is produced by impregnating cows. Once the youngling is born the youngling gets taken away from the mother, while the mother gets connected to several machines, starting the process of milking over a span that lasts for roughly 1 year. The milk they produce isn’t effective in converting the nutrients they eat (3% effectiveness). Then the cow gets impregnated again, thus repeating the same process.

Genetically modifying yeast can make dairy protein fermentation an easier and simpler method. What bioengineers are trying to do is make it the best, most sustainable, type of yeast that can create the milk proteins, in order to make the milk products at the fastest conversion rate possible. Two main proteins that cows produce that are vital to dairy are casein and whey.

If we can make dairy that tastes good (and is the same as traditional dairy), at a comparable price point, no one has to compromise. We would have the dairy we love, at the same availability and convenience as before, just as a much better use of resources.

Genetically Modifying Yeast — The Process

The goal of genetically modifying yeast is to alter its DNA so that it has the same protein-producing genes that cows have — so they can produce the same proteins cows do.

We introduce the protein-producing genes to the yeast cells in the form of DNA. Essentially we’re giving the yeast cells an instruction manual on how to make milk proteins by genetically modifying them to include cow DNA. After we introduce the DNA, we want the cell to replicate the new gene sequence many times so that if one cell was destroyed we have more copies (cloning the cells).

This is the process of “cloning” plasmids so they contain new genetic information.

The genetic engineering process is done through the plasmid of a yeast cell. The plasmid is a circle of genetic material that replicates indefinitely. The role of the plasmid is to transfer genetic information to other parts of the cell. Plasmids exist IN ADDITION to the cell’s main DNA (chromosomes). When they’re extracted, the yeast cell is still able to function because it has its chromosomes. In the process of genetic engineering, the plasmid is extracted, and gene-edited (figure above). A section of the DNA inside the plasmid is cut out, then the DNA sequence that cows use to produce milk proteins is inserted in the cell. The plasmid is then introduced to yeast. It transfers the new genetic information to the chromosomes of the yeast cells. The yeast cells then begin dividing and producing the casein and whey proteins.

The genetically modified plasmid is combined with the host cell to produce a new cell the new genetic information given to the plasmid.

In the case of genetically engineered yeast, yeast is the host cell, and the plasmids are edited to include the cow gene sequence that produces proteins. Once we create the transformed yeast cell, we can make the proteins.

How We’re Going to Produce Large Amounts of these Proteins

Every day, 700 million litres of milk is globally consumed. Not including dairy byproducts. This is A LOT of milk, which means that if we are going to produce milk and dairy with yeast cells instead of cows, we will need a substantial amount of proteins.

The modified yeast plasmid cells (that now has the ability to make cow proteins) are grown in large bioreactor tanks where the cells divide and duplicate. More cells duplicating and dividing means more proteins being produced. In the bioreactor tanks or “fermentation vessels”, the yeast cells are given the necessary nutrients they need to produce the dairy proteins. They’re given all the “food” they need to make casein and whey.

In these tanks, the yeast plasmids carry the new genetic information and communicate it to all parts of the cell (including the chromosomes). Now the yeast is given plant nutrients so it can grow and produce proteins.

Once the yeast cells are fermented to grow protein, they go through a purification process to separate the pure proteins from the GM yeast cells. This leaves just the casein and whey.

Casein and Whey chemical structures

The casein and whey are then packaged and ready to be shipped out to produce dairy byproducts like ice cream and cheese.

Perfect day’s process includes 3D bioprinting Cow DNA

The yeast is genetically modified by 3D printing the genetic sequence of a cow and inserting it in the plasmid of the yeast cell. After the plasmid is genetically modified, it’s introduced to the rest of the cell. However, 3D printing is expensive. A 3D printer could cost $10 000–$900 000. The only way these animal-free products will disrupt the industry is if they’re affordable. The process needs to become cheaper.

The only way we can disrupt the dairy industry is if we make a good tasting alternative (which we’ve already done ) at a comparable market price (which we have left to do).

It takes a lot of resources to brew dairy. First, we need to 3D print cow gene protein sequences, so that we can genetically engineer the plasmids of the yeast cell to contain the genes. Then we need to take out a bit of the plasmid’s DNA and replace it with the cow genes. Then the yeast is put in bioreactor tanks, where it is fed nutrients, and then the proteins are purified.

The process is expensive. The only way to make it affordable is to scale the project. The more dairy production factories we have, the cheaper it is to produce each unit of dairy.

We need a change in the way we make dairy.

Of all the nutrients we feed cows, only 3% are actually available to us in the final products of meat or dairy. 97% of the nutrients are wasted. Dairy is wasteful. It takes lots of water, land and energy to make dairy; the solution is yeast-derived dairy production — we just need to make it cheaper.

Using IoT Sensors to improve this process

Technologies aren’t perfect. Using yeast to create dairy proteins is going to be revolutionary in changing the face of dairy — but the process is expensive and prone to errors. We can use IoT sensors to monitor breweries: possibly cutting down production costs and making the yeast protein producing technology more advanced.

IoT technology will have a revolutionary impact on how we ferment yeast. One of the hardest parts of the fermentation process is monitoring the production of proteins in the bioreactor tanks.

Right now, brewing companies are manually monitoring these tanks through human labour. This is an expensive and unpractical expense.

During the fermentation process, yeast is grown to produce casein and whey. This procedure requires lots of monitoring and understanding how the fermentation vessels work. Using human power to monitor these vessels includes lots of inaccuracy and error. Having an IoT interconnected fermentation-vessel lab would provide many benefits. Including:

  • fewer maintenance costs
  • fewer management costs
  • understanding how the yeast cells grow better but being able to monitor temperature, and behaviour of the cells
  • More accurate analysis of conditions in the breweries; fewer emergencies
  • Optimize the inventory of resources: if we’re able to monitor protein conversion rates, nutrient intake and other factors that affect the yeast during fermentation, we can understand the resources required to produce casein and whey
  • minimize time spent managing resources and inventory
  • work towards tweaking the process to make yeast-protein production cheaper.

All in all, fermenting dairy proteins through yeast cell cultures will change the face of dairy.

Yes, the process needs some perfecting, but the help of IoT monitoring and sensors, we’ll get there.

In a few years, hopefully, the cream in your coffee and the milk in your cereal isn’t made from cows, but through the process of yeast dairy production.

In yeast derived dairy production, yeast is genetically modified so that it has the DNA that tells it how to produce casein and whey. Cow genes are 3D printed and implemented in the yeast — an expensive process.

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Isabella Grandic

Aspiring healthcare infrastructure designer, technologist and scientist.