Engineered Bacteria Create Dairy Proteins for Vegan Cheese

Scientists have successfully engineered bacteria to produce essential milk proteins, paving the way for dairy-free cheese and yogurt alternatives. This innovative approach eliminates the need for animal-derived ingredients while creating products that closely mimic traditional dairy at a molecular level. The research, reported in the journal Trends in Biotechnology on July 20, 2025, highlights two methods for producing casein, a sought-after milk protein vital for both infant and adult nutrition.

The global casein market, valued at US$2.7 billion in 2023, faces criticism for its environmental impact and ethical concerns surrounding animal welfare. As demand for sustainable and cruelty-free dairy options rises, researchers are exploring alternative methods to produce casein. The biotechnology sector has long utilized microorganisms as cell factories for generating biomolecules and dietary supplements. Scientists have now applied this principle to produce recombinant casein proteins through genetic engineering.

One of the challenges in replicating casein is the biological process known as phosphorylation, which involves adding phosphate groups to proteins. This process is crucial for casein’s ability to bind calcium, contributing to milk’s stability and nutritional properties. Additionally, calcium binding facilitates the formation of casein micelles, nanoscale structures that deliver bioavailable calcium and phosphate.

To address the phosphorylation challenge, researchers implemented two strategies. The first involved engineering bacteria to co-express three protein kinases derived from Bacillus subtilis, enzymes that catalyze the phosphorylation process. The second strategy was the design of a phosphomimetic version of αs1-casein, replacing serine residues typically phosphorylated in the natural protein with aspartic acid. This substitution mimics the negative charge and functional effects of phosphorylation.

Following the engineering process, the team conducted structural analyses, calcium-binding tests, and simulated gastrointestinal digestion of the engineered αs1-casein. The findings revealed that both the phosphorylated and phosphomimetic caseins exhibited high calcium-binding capacity, with digestibility and structural properties comparable to cattle-derived casein.

The researchers emphasized that while kinase-mediated phosphorylation offers a route for closely mimicking native casein, phosphomimetic casein provides a simpler method for producing functionally similar proteins. They stated that further quantitative analysis is necessary to maximize the potential of microbial casein production for sustainable and cruelty-free dairy applications.

This groundbreaking research not only has implications for the food industry but also represents a significant step toward more ethical and environmentally-friendly practices in food production. As consumer preferences shift towards plant-based alternatives, the success of engineered bacteria in producing dairy proteins could redefine the landscape of non-dairy products, meeting the growing demand for nutritious and sustainable options.

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