Kinetic profile of the cellular lipid composition in an oleaginous Yarrowia lipolytica capable of producing a cocoa-butter substitute from industrialfats

Cell growth, lipid accumulation and cellular lipid composition of Yarrowia lipolytica growing on mixtures of industrial fats containing stearic, oleic , linoleic and palmitic acid have been studied. During growth, the strain i ncorporated oleic and linoleic acids more rapidly than the saturated fatty acids. Relatively high lipid accumulation (up to 0.44 g of lipids per g of dry matter) was observed when stearic acid was included in the culture medi um. In contrast, substrates rich in oleic acid did not favor cellular lipid accumulation. The accumulated lipids, mainly composed of triacylglycerols (45-55% w/w), demonstrated a different total fatty acid composition compare d with that of the substrate; in all cases, the microorganism showed the un usual capacity to increase its cellular stearic acid level, even if this fa tty acid was not found in high concentrations in the substrate. This permit ted the synthesis of interesting lipid profiles with high percentages of st earic acid and non-negligible percentages of palmitic and oleic acid, with a composition resembling that of cocoa-butter.