Inhibition of malolactic fermentation by Saccharomyces during alcoholic fermentation under low- and high-nitrogen conditions: A study in synthetic media

Abstract

The ability of different wine yeast (Saccharomyces cerevisiae) to inhibit malolactic bacteria (Oenococcus oeni) and the influence of nitrogen were studied using a synthetic grape juice. Malolactic fermentation was induced in fermenting synthetic grape juice or synthetic wines inoculated with different commercial strains of S. cerevisiae. O. oeni was generally inhibited in wines that contained higher concentrations of total SO2 although many yeast strains only inhibited the bacteria during fermentation under high nitrogen conditions. Yeast produced higher amounts of SO2 during fermentation under high nitrogen conditions suggesting that nitrogen affected the malolactic fermentation by influencing yeast SO2 production. However, the production of SO2 by yeast did not always account for the inhibition of O. oeni, suggesting the presence of other inhibitory mechanisms.