Lachancea thermotolerans and Saccharomyces cerevisiae in simultaneous and sequential co-fermentation: A strategy to enhance acidity and improve the overall quality of wine

In the last few years there is an increasing interest on the use of mixed fermentation of Saccharomyces
and non-Saccharomyces wine yeasts for inoculation of wine fermentations to enhance the quality and
improve complexity of wines. In the present work Lachancea (Kluyveromyces) thermotolerans and
Saccharomyces cerevisiae were evaluated in simultaneous and sequential fermentation with the aim to
enhance acidity and improve the quality of wine.
In this specific pairing of yeast strains in mixed fermentations (S. cerevisiae EC1118 and L. thermotolerans
101), this non-Saccharomyces yeast showed a high level of competitiveness. Nevertheless the S. cerevisiae
strain dominated the fermentation over the spontaneous S. cerevisiae strains also under the industrial
fermentation conditions.
The different condition tested (modalities of inoculum, temperature of fermentation, different grape
juice) influenced the specific interactions and the fermentation behaviour of the co-culture of
S. cerevisiae and L. thermotolerans. However, some metabolic behaviours such as pH reduction and
enhancement of 2-phenylethanol and glycerol, were shown here under all of the conditions tested.
The specific chemical profiles of these wines were confirmed by the sensory analysis test, which
expressed these results at the tasting level as significant increases in the spicy notes and in terms of total
acidity increases.