Screening of Aroma-Producing Yeast in Distiller's Grains and Optimization of Culture Conditions

Abstract:

In order to improve the quality of Luzhou-flavor liquor, the yeasts were isolated by traditional microbial separation from the distiller's grains. The strain with high yield of ester was screened by liquid fermentation and identified by physiological biochemical tests and 26S rDNA homology analysis. Finally, the Box-Behnken center combination method was used to optimize the culture conditions for the strain. The results showed an aroma-producing yeast, numbered S5, was isolated from the distiller's grains and identified as Wickerhamomyces anomalus. The optimal fermentation was obtained under the following conditions: initial pH 4.95, fermentation time 3 d, the initial sugar content 6 g/dL. Under the conditions, the total ester content was 7.67 g/L, which was more than 64.2% than that before optimization. Thus the strain can be used to improve the quality of Luzhou-flavor liquor.