Screening of yeasts isolated from Baijiu environments for 2-phenylethanol production and optimization of production conditions.

Abstract

2-Phenylethanol (2-PE) with a pleasant rose-like odor is a valuable aroma compound used in many fields. 2-PE production by yeast is considered a promising alternative to chemical synthesis and extraction from natural materials. In this report, the strain YF1702 produced a significantly higher level of 2-PE when compared with other strains isolated from Baijiu-producing environments. According to morphological properties, physiological and biochemical characteristics, and 26S rDNA sequence analysis, strain YF1702 was identified as Pichia kudriavzevii. The optimal fermentation conditions of YF1702 for producing 2-PE were obtained by single-factor experiments, Plackett-Burman design, steepest ascent design, and response surface methodology. The optimal inoculation conditions for strain YF1702 were 50g/L glucose, 6.0g/L yeast extract, 10.7g/L L-Phe, and 32g/L Tween-60. The optimal fermentation conditions were pH 2.3, 26°C, 210rpm shaking, an inoculum size of 0.4% (v/v), and a loading volume of 25.5mL/250mL for 56h. Under these optimal conditions 2-PE production by YF1702 was 5.09g/L. This strain has the potential to increase the content of 2-PE in Baijiu production and enhance the aroma characteristics of Baijiu.