Impact of <i>Pediococcus parvulus</i> and <i>Saccharomyces cerevisiae</i> on <i>Brettanomyces bruxellensis</i> mousy compound production

The presence of mousy off-flavours in wine, attributed to the production of N-heterocycles by lactic acid bacteria or Brettanomyces bruxellensis, poses a significant challenge in the winemaking industry. This study is the first one to investigate the impact of co-cultures focusing on B. bruxellensis with two common wine microorganisms, Pediococcus parvulus and Saccharomyces cerevisiae on the formation of mousy compounds. The screening was conducted in a synthetic medium under controlled conditions. It reveals the nuanced effects of the microorganism combinations. Depending on the P. parvulus or S. cerevisiae strain co-inoculated with B. bruxellensis a synergistic effect is observed on the 2-acetyltetrahydropyridine (ATHP) production, while an inhibitory effect on 2-acetylpyrroline (APY) production by P. parvulus is highlighted when co-inoculated with B. bruxellensis. These findings shed light on the potential impact of the alcoholic fermentation yeast (S. cerevisiae) on the production of mousy off-flavours. Finally, a correlation between ATHP and 2-ethyltetrahydropyridine (ETHP) appears to be confirmed with a ratio of 1:10 between ETHP and ATHP produced in the N-heterocycles assay medium.