Promotion of autolysis through the interaction of killer and sensitive yeasts: Potential application in sparkling wine production

Changes in yeast population and extracellular protein concentration were me asured in two commercial sparkling wines over 18 months and showed a prolon ged death phase of the yeast which could contribute to a delay in the comme ncement of autolysis. As a means of accelerating the onset of autolysis, in teractions between two K-2 killer strains of Saccharomyces cerevisiae and t wo sensitive strains of S. cerevisiae were investigated. Using protein rele ase as a marker of autolysis, a mixed fermentation of killer and sensitive yeast gave rapid death of the sensitive cells and significantly higher prot ein release than in control fermentations. This behavior was observed in me dia at wine pH and media containing 10% (w/v) ethanol, suggesting that kill er and sensitive yeast interactions may be utilized during sparkling wine p roduction to accelerate the onset of yeast autolysis.