Trans-10, cis-12 Conjugated Linoleic Acid Induces Lipid Degradation and Attenuates Fatty Acid Desaturation in Yeast Saccharomyces cerevisiae

Yeast has been successfully utilized as a model organism to study the antilipogenic mechanism of the trans-10, cis-12 isomer of conjugated linoleic acid (CLA). The isomer lowered triacylglycerol content of yeast if supplemented in the cultivation medium. Also monounsaturated to saturated fatty acid ratio in yeast lipids was reduced in the CLA treated cells. In this study, the metabolic conditions in terms of lipid reduction were examined to clarify the antilipogenic mechanism of CLA in yeast. Triacylglycerol accumulation and degradation were examined and desaturation of trans-vaccenic acid to cis-9, trans-11 CLA was measured in the trans-10, cis-12 CLA treated cells. The study confirmed that triacylglycerol accumulation was not prevented in the trans-10, cis-12 CLA treated cells evidenced by the intensive co-accumulation of oleic acid. In the trans-10, cis-12CLA treated culture the triacylglycerol content started to decrease and cellular biomass increase in the stationary phase after the cells had shifted their metabolism from fermentation to respiratory metabolism. This indicated that yeast used the liberated fatty acids for β-oxidation. The lowered capacity to desaturate the trans-vaccenic acid to cis-9, trans-11 CLA pointed out that also desaturase inhibition hasan important role in the antilipogenic mechanism of the trans-10, cis-12 CLA in yeast.