Japanese scientists have developed a new co-culturing system using rat cells and cyanobacteria to create a low-cost alternative to animal serum for cell growth.
Fetal bovine serum has contamination risks and waste accumulation, and is very costly. In addition, it does not align with the promise of producing meat without killing animals.
Rat liver cells can also secrete the proteins (growth factors) needed for muscle cell growth, providing a serum alternative for cultivated meat production. However, they produce waste metabolites, like lactate and ammonia, which hinder muscle cell growth.
“Although more growth factor-secreting cells and longer cultivation produce larger amounts of growth factors, the downside is that the cells also produce waste products like lactate and ammonia into the medium at the same time, which eventually hinders muscle cell growth,” lead researcher Professor Tatsuya Shimizu from Tokyo Women’s Medical University, explained in the press release.
Cyanobacteria, the solution
To find a waste removal solution, the research team modified photosynthetic cyanobacteria with genes to make them assimilate the harmful waste.
To test its effectiveness, the study focused onestablishingd a co-culturing system with the growth-factor-secreting rat liver cells and the modified cyanobacteria. After collecting the supernatant, they found that the method significantly reduced lactate by 30% and ammonia by over 90%. Additionally, the cyanobacteria produced an abundance of nutrients such as glucose and pyruvate compared to the supernatant collected from where rat liver cells were grown alone.
“Culturing animal cells with photosynthetic microorganisms could help address not only future food security challenges but also ethical concerns and issues related to climate change”
More importantly, when the alternative serum was used to cultivate muscle cells, they found that it tripled the growth rate of muscle cells compared to rat liver cells alone. Due to the successful findings, the scientists conclude that the co-culturing system offers a novel, ethical approach with many applications in cellular agriculture.
“Our study provides a novel low-cost, sustainable cell culture system with broad applicability in various fields involving cellular agriculture, such as cultured meat production, fermentation, biopharmaceutical production, and regenerative medicine.
“Further, as a technology for producing meat without killing animals, culturing animal cells with photosynthetic microorganisms could help address not only future food security challenges but also ethical concerns and issues related to climate change,” said Shimizu.
The research team includes Ph.D. student Shanga Chu and Professor Toru Asahi from Waseda University, Professor Yuji Haraguchi from Tokyo Women’s Medical University, and Professor Tomohisa Hasunuma from Kobe University. Their findings were published in Scientific Reports earlier this year.
