Abstract:In this paper, the conditions for ethyl alcohol production by Saccharomyces cerevisiae Y3401 were optimized, and its aroma-producing characteristics were explored. The ethyl alcohol production conditions were optimized by the single factor step-by-step method and orthogonal experimental design with ethyl alcohol producing medium. Optimum conditions for ethyl alcohol production have been shown as follows: glucose 300 g/L, yeast extract 37.8 g/L, initial pH 5.2, seed age 24 h, the inoculation ratio of 3%, the volume of liquid of 30 mL/250 mL, incubated for 32 h at 30 ℃ and 100 r/min. Under the optimal conditions, the ethanol concentration of Saccharomyces cerevisiae Y3401 was 117.2 g/L, which was increased by 1.24-fold compared with the initial production (52.4 g/L). Volatile compounds of the yeast in sorghum hydrolysate medium were detected by headspace solid phase microextraction coupled with GC-MS. After culture for 32 h at 30 ℃ and 100 r/min, a total of 40 volatile compounds, such as β-phenylethanol, ethyl acetate, phenylethyl acetate, and so on, which are important to the quality of Baijiu. Therefore, Saccharomyces cerevisiae Y3401 can not only produce high-yield ethanol, but also produce a variety of flavor compounds that can improve the quality of Baijiu. These characteristics of Y3401 are beneficial to its application in Baijiu-making.