production of animal proteins by cell systems - New Harvest

Experts’ opinions (3): Technological challenges
• I assume that the technology would involve standard mammalian cell culture techniques
(anchorage-dependent cells on microcarriers cultured to high density in large-scale
bioreactors). This can be challenging. In addition to the standard engineering challenges
(sufficient mass transfer, mixing, etc. while minimizing shear profiles) the costs of goods will
need to be extremely low to be competitive.
• There are many challenges for the production of in vitro meat, but I would say the most
important is the achievement of adult phenotype muscle in vitro, which has never been
reported in the scientific literature. This is important because it is adult phenotype muscle
that has the protein density, texture, and other important features that make meat an
important dietary component. Failing this, what you will have will be more like loose
connective tissue, not "meat" in any real sense of the word.
• There are quite a number of challenges that have to be overcome: (a) Generation of stem cell
lines from farm animal species; b) Proliferation of these stem cells without differentiation; c)
Efficient differentiation into muscle cells; d) Large-scale production of myofibers; e) Largescale
production of cheap growth media.
• Here are some hurdles to be overcome. What are the best (stem) cells? What is the best
design of the bioreactor? And not least in the early phase (if the bioreactor can produce just
cells on some surfaces etc): What is the best way to process the product? In vitro meat
involves some basic biology but there are no fundamentally basic problems.
• The technological hurdles that need to be overcome are: (a) efficient differentiation of the
cells; (b) engineering of tissue that is larger than only a few cell layers; (c) processing of the
cells to something tasty and visually attractive
• To make a product with the required structure that is safe.
• I would suggest research is done to move the muscle cells into a suspension type culture; this
would greatly simplify the manufacturing process and eliminate potentially harmful agents.
Consideration should be made as to the culture vessels, capacity, disposable or permanent
stainless steel.
• Large-scale production, reduction of costs and producing the right texture (bite) are important
hurdles.
• The most critical steps are to be able to produce a serum free cell culture medium at a low
enough price, to be able to produce 3d muscle tissue either from stem cells, satellite cells or
mesenchymal cells having a phenotype very close to normal tissue, and then to be able to
scale up this process to an industrial level.
• An important challenge is to increase the mass of the tissue from a few cell layers with natural
diffusion to many cell layers that still are able to take up nutrients efficiently. Another hurdle is
consumer acceptance. The consumer may not like ‘high-tech’ food.
• In vitro meat may be made (a) through suspension culture of single cells or small cells clumps
that are not differentiated or (b) by tissue culture of differentiated cells. Single cell or cell
clump culture is an established technology that is used for the production of
BioPharmaceuticals with (very) high added value, such as monoclonal antibodies. The major
challenges for meat production based on singe cell technology are in my opinion: (a) The very
high cost of goods of the current processes (must be performed under sterile conditions to
prevent microbial contaminations, use of expensive culture media, etc.) (b) The lack of
resemblance to meat (texture, appearance, etc.). Tissue culture for the generation of muscle
tissue, potentially including blood vessels etc., may result in something more resembling
meat. The costs however may be even higher and the technology and especially the scale-up
still need significant further development.
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