Impact of carbon and nitrogen source variation on B-vitamin accumulation in Yarrowia lipolytica: Toward microbial fortification of food ingredients.

Yarrowia lipolytica is a food-compatible yeast with strong potential for sustainable B-vitamin enrichment of functional food ingredients. This study evaluated the effects of glucose, xylose, mixed, and lignocellulosic sugars, as well as diverse nitrogen sources, on yeast growth and B-vitamin yields in controlled fermentations. Glucose with yeast extract led to the highest biomass and intracellular accumulation of thiamine (B1), niacin (B3), and pyridoxine (B6), while mixed sugars supported maximal intracellular folate (B9) content. Intracellular B-vitamin levels were consistently higher with yeast extract than with defined nitrogen sources. Cobalamin (B12) was detected in biomass under all substrate and nitrogen conditions; based on current knowledge of Y. lipolytica metabolism and the presence of trace B12 in yeast extract, these observations are consistent with uptake and retention from the medium rather than de novo biosynthesis. Results indicate that nutrient formulation, particularly the use of renewable sugars and organic nitrogen, can be strategically tuned to generate Y. lipolytica biomass with distinct B-vitamin profiles suited to different food fortification scenarios. The demonstrated use of commercial lignocellulosic sugar streams underscores the compatibility of this process with food-grade industrial substrates and circular-economy concepts, providing a practical basis for deploying B-vitamin-enriched yeast as a functional ingredient in plant-based beverages, cereal products and other fortified foods.