Relationship Between Sluggish Fermentations and the Antagonism of Yeast by Lactic Acid Bacteria

Abstract

Lactic acid bacteria isolated from commercial wines undergoing slow/stuck alcoholic fermentations and from wines without any known problems were tested for antagonistic activity against wine yeasts. Using a microbiological medium screening method, the majority of bacterial strains tested did not retard growth of <i>Saccharomyces bayanus</i> (strain Prise de Mousse) or <i>S. cerevisiae</i> (strain Epernay), with the exceptions of <i>Leuconostoc oenos</i> strain OENO and unidentified strains YH-15, YH-24, and YH-37. To determine whether or not these organisms could cause a slow/stuck fermentation of a grape juice, bacterial strains were inoculated into sterile-filtered Chardonnay grape juices at initial populations of <i>ca</i> 10⁵ cfu/mL. Two days later, either Epernay or Prise de Mousse was inoculated into the same juices at <i>ca</i> 10⁵ cfu/mL. Inoculation of <i>Lc. oenos</i> did not result in slow/stuck alcoholic fermentations. However, inhibition of the fermentations catalyzed by Epernay were observed in the presence of YH-24 or YH-37, in contrast to fermentations with Prise de Mousse. Strain YH-15 greatly inhibited the alcoholic fermentations by both yeast strains. Wines inoculated with YH-15 had significantly higher concentrations of volatile acidity (≈=0.30 g/100 mL) than control wines (≤0.037 g/100 mL) or wines inoculated with YH-24 or YH-37 (≤0.055 g/100 mL). Other compositional differences were observed.