At a Glance
- Scientists face a significant challenge in creating recombinant casein because it requires a specific modification, called phosphorylation, to be functional.
- One successful strategy involved engineering E. coli to co-express bacterial kinases, which correctly added phosphate groups to the lab-made casein.
- An alternative phosphomimetic approach was also developed by substituting specific amino acids to mimic the effects of phosphorylation without requiring an additional step.
- Lab tests confirmed that both engineered caseins exhibited high calcium-binding capacity and structural integrity comparable to that of natural bovine casein.
- This research is a crucial step toward the commercial production of sustainable and functional animal-free dairy proteins for the food industry.
Scientists have successfully engineered bacteria to produce casein, a key protein in milk, marking a significant step toward creating animal-free dairy products that are molecularly identical to the real thing. This breakthrough, published in the journal Trends in Biotechnology, addresses a significant challenge in food science: creating sustainable, cruelty-free alternatives that replicate the taste, texture, and nutritional value of traditional dairy products. By using the common bacterium Escherichia coli as a tiny protein factory, researchers are paving the way for cheeses and yogurts made without a single cow.
The secret to casein’s unique properties lies in a natural process called phosphorylation. This is a post-translational modification in which phosphate groups are attached to the protein after it is synthesized. This process is critical for casein’s ability to bind with calcium and form structures called casein micelles, which give milk its stability, white color, and nutritional benefits. While scientists have long been able to produce basic proteins in microbes, getting the phosphorylation just right has been a persistent roadblock, preventing lab-made caseins from functioning like their natural counterparts.
To solve this problem, the research team developed two innovative strategies. In the first method, they engineered the bacteria also to produce specific enzymes, called kinases, from another bacterium, Bacillus subtilis. These kinases acted as molecular workers, correctly attaching phosphate groups to the lab-grown casein. The second approach was a clever workaround called a phosphomimetic strategy. Instead of adding phosphate, scientists replaced key amino acids in the casein protein with different ones that naturally mimic the negative charge and function of phosphorylation, effectively tricking the protein into behaving as if it were phosphorylated.
Both the phosphorylated and phosphomimetic caseins were found to be highly successful. Laboratory tests demonstrated that they could effectively bind calcium and possessed structural and digestive properties comparable to those of casein from cow’s milk. While the kinase method produces a protein that more closely resembles natural casein, the phosphomimetic version offers a potentially more straightforward path to large-scale production. This foundational research demonstrates that a sustainable, animal-free dairy future is not only possible but also scientifically within reach.
References
- Balasubramanian, S., Mobasseri, G., Shi, L., Jers, C., Køhler, J. B., Boire, A., Berton-Carabin, C., Mijakovic, I., & Jensen, P. R. (2025). Production of phosphorylated and functional αs1-casein in Escherichia coli. Trends in Biotechnology, S0167779925001817. https://doi.org/10.1016/j.tibtech.2025.05.015
- Mondal, S. & Phys.org. (2025, July 20). Real milk proteins, no cows: Engineered bacteria pave the way for vegan cheese and yogurt. Phys.Org; Phys.org. https://phys.org/news/2025-07-real-proteins-cows-bacteria-pave.html
