Micro Meat (YC S21) – Technology for scaling cultivated meat

Hi HN community, Anne-Sophie and Vincent here, the founders of Micro Meat. We’ve developed new techniques for producing cultivated meat.

Cultivated meat is just real meat based on animal cells, but instead of getting meat by growing animals, it is grown in bioreactors. This will soon be much better for our planet: less land, water and feed required for the animals, less environmental impact from cutting down forests for farmland and feed production, less antibiotics, and of course, far less harm to animals.

The basic process for cultivating meat is known, but there remain difficult problems in bringing it to mass production. I’ll describe the process, the problems, and our solution.

Cultivating meat is similar to brewing beer, but instead of growing yeast, we grow muscle cells (plus fat cells for deliciousness!). The process begins with a handful of stem cells that are isolated from an animal. Initially, the volume is tiny and the cells are handled very carefully. They are mixed with medium, which is a mixture of growth factors like insulin, along with amino acids, and other nutrients that they need to grow. Then they are proliferated (multiplied) to upwards of 10M cells per mL.

After proliferating, the overall volume gets above 250 mL and shear stresses start to become an issue, meaning the cells get damaged and break apart. Traditional bioreactors use large impellers for mixing the cells and medium, along with a sparger which adds gasses like CO2 and O2. The impeller, gas bubbles, baffles, and internal surfaces are all locations where cells encounter damaging shear stresses. That’s not a problem if you’re cultivating bacteria, yeast, or other microorganisms that have a high tolerance for this. But mammal, bird and fish cells are very intolerant of such stresses, making it hard to cultivate meat. This is the first problem we address.

After the cells have proliferated from a very small volume to tens or hundreds of liters, they are still a mass of single, unorganized cells. In order to get delicious meat we need to make those individual cells merge and differentiate together to form actual muscle tissue that has the right texture. When cells differentiate, they change from being stem cells, into specialized cells and structures, for example, inside the cells myosin heavy chains develop along the actin cell-skeleton. These myosin-actin complexes are basically the motors of the muscle. For this, the cells get seeded onto constructs called scaffolds. A scaffold is like housing for the cells, a structure where cells can easily move into and grow. We usually try to make scaffolds that mimic the cells' natural environment in the animal's body so they feel as at home as possible.

Traditional methods pour the proliferated cells on top of the scaffold and hope that they “stick”. This is easy, but results in tissues that aren’t uniform—in some places the cells attach well, in other places not at all. Additionally, the scaffolds are not always edible—a major problem if you’re producing meat! Consistent cell distribution throughout the scaffold is the second problem we address, and edibility is the third.

The scaffolds are then reintroduced to reactors for another proliferation or differentiation, depending on the process. The cells are given time to mature, where they finalize their structure, orientation and internal make-up. At this point, you have muscle tissue, and the only thing left to add is components such as fat, which add to the taste and texture of the meat.

This process is immensely complex and the cost to produce it at scale is tremendous. To bring cultivated meat to the masses, the complexity and cost problems have to be solved. Many companies have spent years on R&D, but are still not able to produce at larger scales. We want to change that.

We asked ourselves, how could we protect these cells while they are in the harsh environment of the reactor, while also creating homogenous, high quality 3D scaffolds that are consistent throughout?

Our method addresses shear stress by shielding the cells within the scaffold. Because the cells are embedded inside the scaffold they don’t feel the damaging wall shear stresses inside a bioreactor, only the surface of the scaffold itself is exposed to them. Our scaffold composition is designed to maintain typical diffusion properties, so even though the cells are shielded and don’t touch the medium (which contains the nutrients) the nutrients still make it to the cells. As time goes on and the cells differentiate and mature, they now have a 3D construct where they can begin to develop into the texture of meat. This process enables cells to be seeded at nearly any rate, from only a few grams per minute to over thousands of kilograms per minute. This means our technology can be used from the research stage all the way through full production.

We don’t intend to sell meat ourselves. Our business aims at helping other companies to go to market faster, by eliminating the complexity associated with scaffold seeding. Our scaffolding technology easily integrates into any bioreactor train on the market. Users can purchase or lease the machine for around $250-$500, depending on their needs. Our scaffold bio-inks are universal for mammals, birds and fish, and can be purchased either as single orders or as a subscription, ranging from volumes of one liter up to thousands. Each liter of scaffold costs less than $2 and produces 2 to 5 kilograms of meat.

A word on our backgrounds: I (Anne-Sophie) am a biomedical and tissue engineer with a PhD from ETH Zurich and Masters from Imperial College London. I’ve been working on creating functional biological tissues in the lab most of my professional career. I love animals and have been a vegetarian since I was 8 years old. I also love our planet and decided to use my tissue engineering skills to help change our food system. And I love good food! so the idea of amazing new food products is highly appealing to me.

I (Vincent) am a space systems engineer. I’ve been building, testing, launching and analyzing the Delta IV, Atlas V, New Glenn and SLS rockets for the last 7 years. I’ve probably had my hands in almost every stage of launch system development, from napkin sketches to saying go for launch. Space has always been awe-inspiring to me, but the climate crisis needs direct attention in order to stop, reverse and survive the impacts of climate change. After researching the impact the livestock industry has on our planet, I knew I wanted to get involved to stop it.

If you’re interested in learning more or collaborating, you’re warmly welcome to reach out to us at [email protected] We’d love to hear your thoughts on any of the above, from cultivated meat in general to the details of the production process, and whatever else you’d like to ask or share!

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