Effect of mixed culture of Saccharomyces cerevisiae and Pichia anomala on fermentation efficiency and flavor compounds in Chinese Liquor

Abstract:

[Objective] To increase ester content and maintain fermentation performance, mixed fermentation of Saccharomyces cerevisiae and Pichia anomala in wheat bran liquid medium were used. [Methods] S. cerevisiae and P. anomala were inoculated using mixed or sequential modes. Fermentation efficiency and the content of ethyl acetate during fermentation process, and volatile compounds in ultimate fermentation liquid were detected with pure culture of yeast as controls. Interactions between yeasts were preliminarily studied through cell-free systems. [Results] Using sequential inoculation, growth of P. anomala wasn’t inhibited by S. cerevisiae and two species could reach high biomass. At the end of fermentation ethanol content was 20.17 g/L, which reduced 9.14% than pure culture of S. cerevisiae. But the concentration of ethyl acetate was 0.74 g/L, which increased 80% compared to P. anomala monoculture. The mixed fermentation of S. cerevisiae and P. anomala produced more esters, less alcohols and fatty, and improved flavor characteristics of fermentation liquid. Analysis of cell-free system showed that carbon source was an important factor to affect growth of S. cerevisiae and metabolites obviously inhibited propagation of P. anomala. [Conclusion] Mixed fermentations of S. cerevisiae and non-Saccharomyces provided a feasible way to improve flavor complexity and obtain speci?c characteristics of fermentation products.