Screening of high yield 2-phenylethanol strain and the application in rice-flavor Baijiu

To improve the flavor of rice-flavor (mixiangxing) Baijiu, high-yield 2-phenylethanol strain was screened from strains bank and rice-flavor Baijiu mash through preliminary screening with olfaction and secondary screening with fermentation, the strain was identified by molecular biological techniques, the tolerance was analyzed, and the optimal conditions for 2-phenylethanol production were optimized by single-factor experiments. The results demonstrated that strain No. 15 with high yield 2-phenylethanol was screened, and the strain No. 15 was identified as Saccharomyces cerevisiae by molecular biology technology. The strain No. 15 had good tolerance and could tolerant pH 3, temperature 40 ℃, 12% ethanol, 0.5% acetic acid, and 10 g/L NaCl. The rice-flavor Baijiu was brewed by the strain No. 15, and the contents of 2-phenylethanol in Baijiu increased by 5%. Through single-factor experiments, the optimal culture conditions were determined as follows: glucose 100 g/L, yeast extract 5 g/L, L-phenylalanine 25 g/L, magnesium sulfate 0.5 g/L, and potassium dihydrogen phosphate 5 g/L. Under these optimal conditions, the 2-phenylethanol mass concentration produced by strain No. 15 reached 1.77 g/L. The results showed that the strain No. 15 had a good application prospect in improving the flavor of rice-flavor Baijiu.