During fermentation for ethanol production, yeasts are subjected to different
kinds of physico-chemical stresses such as: initially high sugar concentration and low
temperature; and later, increased ethanol concentrations. Such conditions trigger a series of
biological responses in an effort to maintain cell cycle progress and yeast cell viability. Regarding
osmostress, many studies have been focused on transcriptional activation and gene
expression in laboratory strains of Saccharomyces cerevisiae. The overall aim of this present
work was to further our understanding of wine yeast performance during fermentations
under osmotic stress conditions. Specifically, the research work focused on the evaluation
of NaCl-induced stress responses of an industrial wine yeast strain S. cerevisiae (VIN 13),
particularly with regard to yeast cell growth and viability. The hypothesis was that osmostress
conditions energized specific genes to enable yeast cells to survive under stressful
conditions. Experiments were designed by pretreating cells with different sodium chloride
concentrations (NaCl: 4%, 6% and 10% w/v) growing in defined media containing D-glucose
and evaluating the impact of this on yeast growth and viability. Subsequent fermentation
cycles took place with increasing concentrations of D-glucose (20%, 30%, 40% w/v)
using salt-adapted cells as inocula. We present evidence that osmostress induced by mild
salt pre-treatments resulted in beneficial influences on both cell viability and fermentation
performance of an industrial wine yeast strain.