Use of a submerged yeast culture and lysozyme for the treatment of bacterial contamination during biological aging of sherry wines

The aim of this study was to determine the effect of a submerged culture of “flor” velum yeast and lysozyme as treatments against bacterial contamination by lactic acid and acetic acid bacteria during the biological aging of sherry wine. Different submerged culture treatments with lysozyme were performed. To assess these treatments, we performed laboratory assays with wine spoiled by lactic acid bacteria (LAB) and/or acetic acid bacteria (AAB) selected from the “solera” sherry wine cellar system. The results indicate that lysozyme should be added to submerged culture conditions after the start of the yeast growth phase. The application of lysozyme at a dose of 12.5 g/hL and submerged culture conditions was very effective for the treatment of advanced heterolactic fermentation during the biological aging of wines, thereby inhibiting the LAB population and reducing the volatile acidity of the wines (<0.1 g/L). Similarly, the submerged culture was a very effective tool for the treatment of AAB contamination of recovering wines with high volatile acidity and the removal of AAB without alcohol correction of the wine. The combined lysozyme and submerged culture treatment was very effective at removing bacteria from the wine, reducing volatile acidity and preventing acetification.