Influence of oxygen addition during growth phase on the biosynthesis of lipids in Saccharomyces cerevisiae (M(3)30-9) in enological fermentations

The fatty acid, phospholipid and sterol composition of one strain of Saccha romyces cerevisiae under different oxygen levels during grape must fermenta tion was studied. Anaerobiosis partially inhibited yeast growth and resulte d in a drop in the unsaturation index of the fatty acids throughout the fer mentation, as well as an abnormally low ergosterol/phospholipid ratio. Aera tion after 48 h of fermentation in anaerobiosis stimulated growth and incre ased cellular viability, as well as raised the unsaturation index of fatty acids. Although the ergosterol/phospholipid ratio remained low in the days following the aeration, by the end of the fermentation the value was that c onsidered optimum for the maintenance of membrane functions.