New yeast-based approaches in production of palmitoleic acid.

Palmitoleic acid is found in certain dairy products and has broad applications in medicine and cosmetics. We tried to find a suitable producer of this acid among traditional biotechnological yeast species (Kluyveromyces polysporus, Torulaspora delbrueckii, Saccharomyces cerevisiae) characterized by high biomass yield and Candida krusei, Yarrowia lipolytica and Trichosporon cutaneum accumulating large amounts of lipids. The main factor affecting the content of palmitoleic acid was found to be the C/N ratio in the culture medium, with ammonium sulfate as an optimum nitrogen source leading to highest biomass yield with concomitantly increased lipid accumulation, and an increased content of ω6-linoleic acid, the precursor of prostaglandins, leukotrienes, and thromboxanes. We found that C. krusei can be conveniently used for the purpose, albeit only under certain cultivation conditions, whereas S. cerevisiae can produce high and stable amounts of palmitoleic acid in a broad range of cultivation conditions ranging from conventional to nutrient limitations.