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 Saccharomyces bayanus (strain Prise de Mousse) or S. cerevisiae (strain Epernay), with the exceptions of Leuconostoc oenos 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 ca 10⁵ cfu/mL. Two days later, either Epernay or Prise de Mousse was inoculated into the same juices at ca 10⁵ cfu/mL. Inoculation of Lc. oenos 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.