Kinetic study of growth, lipid and carotenoid formation in beta-carotene producing Rhodotorula glutinis

摘要

The oleaginous and red yeast Rhodotorula glutinis CCY 20-2-26 is known for its high-storage lipids accumulation in cells as well as for beta-carotene biosynthesis. The work is focused on the study of lipogenesis and carotenoid pigments formation by the yeast grown in media with four different C/N ratios (20:1, 50:1, 70:1 and 100:1). Total fatty acids accumulation in cells reached the maximal value of 48% and yielded up to 8.9 g fatty acid/L media under C/N 70:1. On contrary, while the highest pigment accumulation in the yeast (1268 mu g/g of cells) was found at the C/N ratio of 20:1, the maximal carotenoid yield (mainly beta-carotene) of 12.7 mg/L was obtained under 50:1 ratio. Calculation of kinetic parameters of metabolites production revealed the metabolic correlations among glucose consumption, lipogenesis and carotenoid biosynthesis. It was demonstrated that glucose exhaustion resulted in reduction of growth and lipid accumulation in cells. Then, storage fatty acids, especially palmitic and oleic acids, begun to be degraded by beta-oxidations and formed acetyl-CoA which was especially used for biosynthesis of beta-carotene. This is the first study providing the new hypothesis about the metabolic connection between fatty acids and beta-carotene metabolism in the red yeasts.