Engineering Lactobacillus casei to Enable Sustainable Home Production of Vitamin A-Enriched Dairy Foods by At-Risk Mothers

Vitamin A deficiency (VAD) is a major problem in the developing world that disproportionately affects pregnant women, children, and infants. Vitamin A's role in development and immunity make it critically important to natal/neonatal health. Fermented dairy products, particularly yogurt, are traditionally made by women using small-scale fermentations, often on a per-household basis. In all fermentations, local strains of lactic acid bacteria (LAB) have been utilized for generations as yogurt starter cultures, continuously cultured by a process called back-slopping. We propose to engineer a lactic acid bacteria (LAB), Lactobacillus casei, to produce the provitamin A carotenoid, beta-Carotene. This strain could then be added to local starter cultures, resulting in beta-Carotene-enriched dairy products without any change in production methods. Once this strain is added, it would remain part of the local starter cultures, producing beta-Carotene-enriched products indefinitely. Because these products would contain beta-Carotene and not Vitamin A itself, there would be no risk of hypervitaminosis. This technology, combined with education and outreach, could enable at-risk mothers to provide Vitamin A supplementation for themselves, their family, and even their community in a safe and sustainable way.