Aim: To verify a possible correlation between cell lipid composition, expression of key genes in lipid metabolism and fermentative behaviour of Saccharomyces cerevisiae wine strains.
Methods and results: The fermentative abilities of two commercial wine strains of S. cerevisiae were tested under stressful conditions. Cell number, glucose and fructose concentrations, expression of ACS1, ACS2, ACC1, OLE1, ERG9, ERG10, ARE1 and ARE2 and lipid content were evaluated. The strain that failed to complete the fermentation had lower amounts of C16:1 and C16:0 fatty acids at the beginning of fermentation (0 h) and late logarithmic phase (72 h). While the amount of C18:1 in this strain was lower than that in the strain that completed the fermentation at 0 h, same levels were observed for both strains at 72 h. The sterol levels were generally higher in the strain that failed to complete the fermentation. Gene expression generally increased from the beginning of the fermentation to the late logarithmic phase in both strains.
Conclusion: A positive correlation between good fermentative ability, elevated fatty acid content and ACC1 gene expression has been identified.
Significance and impact of the study: The cell lipid content at the time of inoculum and expression of ACC1 gene of starter strains should be carefully considered in order to identify the possible stuck/sluggish fermentations.