Quantitative study of interactions between Saccharomyces cerevisiae and Oenococcus oeni strains

Area of Science:

• Microbiology
• Enology
• Food Science

Background:

• The interplay between yeast (Saccharomyces cerevisiae) and lactic acid bacteria (Oenococcus oeni) is critical for successful winemaking.
• Understanding these interactions is key to controlling malolactic fermentation (MLF) and wine quality.

Purpose of the Study:

• To investigate the influence of specific Saccharomyces cerevisiae strains on Oenococcus oeni growth and malolactic activity.
• To explore the impact of different bacterial strains on yeast fermentation performance.

Main Methods:

• Sequential fermentation strategy simulating winemaking conditions.
• Co-culturing of four Saccharomyces cerevisiae strains with Oenococcus oeni.
• Analysis of bacterial growth, malolactic activity, and key biochemical parameters (ethanol, SO2, fatty acids, nitrogen).

Main Results:

• Significant inhibition of Oenococcus oeni was observed with three out of four yeast strains, linked to reduced bacterial growth, not activity.
• One yeast strain unexpectedly stimulated Oenococcus oeni growth and malolactic activity, a novel finding.
• Biochemical profiles showed minor variations in ethanol, SO2, fatty acids, and nitrogen, insufficient to explain inhibition or stimulation.

Conclusions:

• Saccharomyces cerevisiae strains exert differential effects on Oenococcus oeni, ranging from significant inhibition to stimulation.
• The specific bacterial strain plays a critical role in the outcome of yeast-bacteria interactions.
• The mechanisms behind yeast-induced bacterial inhibition and stimulation remain largely unexplained and warrant further investigation.