Improving acid tolerance in Oenococcus oeni by Adaptive Evolution

Oenococcus oeni is a lactic acid bacterium (LAB) mainly responsible for the malolactic fermentation (MLF) in wine. MLF plays an important role in determining the final quality of wines [1]. Even though this LAB is naturally present in musts, wines and oenological environment, spontaneous MLF are usually unpredictable because of the stressful conditions and especially due to acidity [2]. The consequence of the mismanagement of this step might lead to the depreciation of wine quality. To obtain a clone more tolerant to acidity, we undertaken to replicate O. oeni in a temporally varying environment (pH 5.3 to 3.2) to improve acid tolerance. To discriminate stress tolerance of evaluated populationsversus parental strain an ethanol or acid stress were improved to both population.