Fatty acid composition of malolactic Oenococcus oeni strains exposed to pHand ethanol stress

The fatty acid composition of several Oenococcus oeni strains was deter min ed during cell Growth under optimal conditions and after cell transfer to a medium containing malic acid at pH 3.2 with and without ethanol. In all st rains, C18:1 acids decreased and C19 cyclopropane acids increased with cult ure ageing, while, after cell exposure to ethanol, mainly the C18:1 Delta9 acid increased. The extent of these modifications was strain dependent. Num erical analysis of fatty acid profiles always grouped the strains into two clusters at r close to 0.65. In the presence of ethanol at low pH, only one strain was unable to breakdown malic acid, but its fatty acid composition did not differ from the other strains. Thus, the malolactic capability of O . oeni strains under pH and ethanol stress does not seem to be correlated t o their fatty acid composition.