Progress has been made on every aspect of cultivated meat production from media formulations to cell lines. But the economics won’t add up unless the industry develops new bioreactors purpose-built for high-volume, low-value food, as opposed to low-volume, high-value pharma, says Mission Barns.
Founded in 2018 by former Eat Just scientist Eitan Fischer, San Francisco-based Mission Barns grows cultivated pork fat in proprietary bioreactors it claims can dramatically improve the efficiency of the production process. The fat is then combined with plant-based proteins to create meat alternatives such as sausages and bacon.
Pending regulatory approval, the firm plans to launch finished products at a handful of outlets next year to validate its product and process; it ultimately aims to be a B2B supplier of fat to the plant-based and cultivated meat industry.
Unlike some other startups in the field, Mission Barns is not genetically engineering naturally adherent cells (that need to attach to something to grow) so they can grow in standard stir-tank bioreactors in liquid suspension, VP of technology Saam Shahrokhi told AgFunderNews.
“We’re engineering systems to [work with] the cells, rather than engineering cells to work with traditional systems [bioreactors]. Existing bioreactors can’t be used to effectively produce non-GM cultivated muscle and fat.”
Pros and cons of existing bioreactors
Single-cell suspension stir tank bioreactors can achieve high cell densities and make cell harvesting relatively easy, says Shahrokhi, who was employee number one at Mission Barns, which has raised $60 million to date from investors including Lever VC, Gullspang Re:Food, and an undisclosed European meat company.
However, these bioreactors are poorly suited to fat cells, which become buoyant and crowd at the liquid surface in the bioreactor, consuming the local nutrients and oxygen and disrupting the vessel’s homogeneity, said Shahrokhi. While speeding up the mixing rate can help, he says, this can damage the cells.
Single-cell suspension bioreactors are also poorly equipped to facilitate cell differentiation and tissue formation, explained Shahrokhi. “Adherent cell cultures are necessary for eventual tissue formation and integration with edible scaffolds, allowing both proliferation and tissue formation to occur in the same production vessel.”
That said, current adherent systems are not designed for large-scale cell culture, while harvesting cells can also be extremely challenging, he claimed. “Currently, there are no viable off-the-shelf adherent ‘ designs for large scale cell culture.”
‘A cell culture system that addresses the limitations of existing adherent culture and suspension culture bioreactors’
To achieve the best of both worlds, Mission Barns has engineered a novel adherent bioreactor system to “fit the cells’ natural, preferred mode of growth,” he explained. “We’ve created a cell culture system that addresses the limitations of existing adherent culture and suspension culture bioreactors and allows us to scale the production of cultivated meat or cultivated fat without the need to modify the cells and face associated hurdles at scale.”
Thanks to efficient mass transfer and dense cell packing, Mission Barns’ bioreactor has high volumetric productivity without compromising harvestability, claimed Shahrokhi, who said the company has also developed animal-component free cell culture media and uses non-GMO cells.
“We’ve streamlined the harvesting process, allowing for efficient collection of cells from a reusable substrate. Our bioreactor also has the potential to grow and harvest whole-tissue products.”
Crucially, he claimed, it can also be scaled up for industrial manufacturing. “Even at high scales, media can be thoroughly mixed without exposing cells to excessive shear forces.
“Our bioreactor also separates cell flow from fluid [e.g., media] flow [as the cells are attached to a substrate] and is designed so the space cells grow in doesn’t impede the ability to flow liquid through the bioreactor,” added Shahrokhi, who said Mission Barns uses animal-component-free, “cheap, food-grade” process reagents and substrates for coating, washing, and harvesting.
He added: “There are a lot of advantages that come with cell flow being decoupled from liquid flow; you kind of have perfusion built into your bioreactor already [making it easy to cycle out media, as you don’t have to separate it from the cells, which are attached to a substrate].”
The process of harvesting is “very simple,” meanwhile. “We simply pump in a dissociation solution, which gets the cells off of our reusable food-grade substrate, and then we pump out the cells within the dissociation solution. At that point, you treat it just like you would downstream with cells grown in suspension culture. The difference is that the cells are already differentiated [into fat cells] in our system.”
Growing fat vs muscle
As for Mission Barn’s decision to focus on growing fat versus muscle in the first instance, he said, “One advantage is that you can reduce media costs, because you’re using primarily glucose rather than amino acids as your feed source, so our media cost is in the single digits dollars per liter. Plus, the oxygen demand of fat cells is significantly less than that of muscle cells.
“Then when it comes to differentiation and maturation, we don’t need to create myotubes [muscle tissue]. Instead, we just have to put the cells into a state of metabolism, where they’re filling up these lipid droplets inside them with fat. So from a mechanical perspective, it is significantly less complex.”
He added: “The cells are also a bit easier to work with as opposed to cells that become muscle cells. Right now, we’re focused on pig fat, but the advantage of our bioreactor is that it’s cell line agnostic, so a lot of the process development we do is applicable to fat of all kinds of species. The bioreactor can also be used for muscle cells.”
Progress to date
To date, Mission Barns has conducted 100+ successful runs in its pilot facility in San Francisco, and claims that with continued improvements on media use efficiency, bioprocess scale up innovation, and supply chain optimization for raw materials, it can reach price parity with conventional pork.
According to deputy CEO Cecilia Chang: “We have a dual business model. On the B2C side, we’re able to get to market quickly and launch our proof of concepts, which also enables us to demonstrate to potential b2b partners that there’s consumer interest in these kinds of products.
“And then on the B2B side, this is a critical way for us to grow and scale faster with an asset-light approach. So our model will be to license the technology, not just the novel bioreactor but also a bunch of other proprietary things we’ve developed across the tech stack, to large players that have existing infrastructure, and downstream capabilities, already in place, marketing, distribution, and so on.
“They would then manufacture the Mission fat themselves and use it in their own finished products.”
As to whether existing alt meat brands would want to compromise their 100% plant-based credentials by using cultivated animal fat, even if no animals were harmed in its production, she said: “I think we’re talking about creating a new category. For most consumers [who are not vegan or vegetarian], what matters is that food tastes delicious, and is ideally good for them, sustainable and humane.”
And notably, very small amounts of animal fat—which is easier and quicker to grow than muscle—can make a significant difference to the eating experience of meat alternatives, she claimed.
“Based on the sensory testing we’ve done to date, we can achieve significant and meaningful sensory improvement into a plant-based product with a relatively small amount of cultivated fat, as it contains a lot of volatile compounds and aromas that we associate with the deliciousness of meat.”
Asked about the regulatory process, Shahrokhi said: “We’ve been engaged with FDA for some period of time and we’re expecting to get approval relatively soon.”
‘This is truly disruptive technology’
Stepping back to look at the cultivated meat space more generally, Chang said: “There was a lot of excitement about this space and maybe that led certain people to develop expectations about the progress and speed of the industry that were unrealistic.
“This is truly disruptive technology; we’re figuring out how to grow real meat without an animal at scale, and the reality is that that doesn’t take five years. If you look at the trajectory of solar power, electric vehicles, and other new industries, they took many years to grow and evolve, so it was probably never realistic to expect cultivated meat be on every Walmart shelf in five years. What we’re seeing now is a correction around what are the expectations and what’s realistic for the industry?”
She added: “There are definitely still investors who see the long term potential of this space and are long term thinkers. They believe in the transformational power of cultivated meat and are looking for people who have realistic timelines and unique technology platforms like ours, who could very much win in this space.”
Further reading:
Tufts professor has ‘zero worries’ about long-term viability of cultivated meat
UPSIDE Foods initiates new round of layoffs as state lawmakers take aim at cultivated meat
