Scaling up cultured meat : the technical challenge
Lab-grown meat could change the food system. But it has to scale up first, and it’s not an easy task.
Cultured meat could be affordable in years to come, and allow us to keep up with rising meat demand, while reducing the carbon footprint and waste related to meat production. If it’s great, we must remember that there are some challenges along the road.
Until today, most of tissue engineering has happened in the medical field. Which means that existing production processes and facilities are not entirely suitable to cultured meat production. Indeed, the scale required for making cultured meat a commodity is expected to be the largest ever for tissue engineering (Stephens et al., 2018), and to achieve that, some work needs to be done.
What’s the difference between established bioprocesses and cultured meat bioprocessing ? Essentially, it’s the complexity of the environment for both proliferation and differentiation of muscle cells. Today, publications focus on cell therapies, and demonstrate mesenchymal stem cell expansions in bioreactors up to 5 litres. The thing is that… to produce 1kg of protein from muscle cells, we would need a tank bioreactor in the order of 5000 litres. If this volume is suited to established bioprocessing, it is yet unproven in tissue engineering and mesenchymal stem cell expansion… or simply said, meat culture.
As things stand, the question is whether to produce cultured meat in a few large bioreactors (scale-up) or in many smaller bioreactors (scale-out). For the moment, it seems that the scale-out approach is highly labour intensive and costly. Thus, according to Stephens, making cultured meat a commodity will more likely depend on the implementation of scaffold and bioreactor conditions that enable cell differentiation in larger bioreactors.
What are the perspectives ? As Moritz et al. have shown, working on the large-scale production of cultured beef, commercially available systems (microcarrier or cell-aggregate based) are a good start but need to be optimized for bovine satellite cells (if you want to start with cultured beef). The major limitations in up-scaling systems seems to be costs (microcarriers), apoptotic cells (aggregates) and lack of commercial availability (packed bed bioreactors). However, it is anticipated that the optimization of large-scale cell culture as performed for other stem cells can be translated into successful protocols for bovine satellite cells resulting in resource and cost efficient cultured beef.
These studies are promising. Now, we need to know whether their results will be also valid for other types of cultures (pork, chicken, fish).
Another concern is how cultured meat companies will concretely develop such systems, while respecting other constraints, like energy consumption. I’m currently working on the topic as a side project with an engineer friend. If you want to contribute, let me know at tristanroth(at)hotmail(dot)com.