Abstract: In this research, yeast strains were isolated and purified from Jiangshui, a traditional Chinese fermented vegetable food, by the streak plate method. The isolates were screened for aroma-producing ability by sensory evaluation, analysis of their fermentation properties and semi-quantitative analysis of the volatile compounds produced by them using gas chromatography-mass spectrometry (GC-MS). The selected strain was identified by physiological and biochemical tests and molecular biology. The enrichment culture for this strain was optimized using one-factor-at-a-time (OFAT) method and response surface methodology (RSM). A total of 16 yeast isolates were obtained. The strain Y16 was selected out of these and was identified as Hansenula anomala. The optimum medium formulation was determined to 10 °Be′ wort plus 11.0 g/L glucose, 2.3 g/L beef extract, and 0.8 g/L KH2PO4. In this enrichment medium, the final cell concentration reached 8.75 × 108 cells/mL, which was more than 4 times as high as that in the initial wort fermentation medium. Simultaneously, the ethyl acetate yield reached 256.35 μg/mL, and the limonene yield reached 0.083 μg/mL, which increased by 25.39% and 31.75% respectively in comparison with the initial fermentation medium. To sum up, the efficient aroma-producing strain could provide a source of direct vat set (DVS) starter culture for Jiangshui.

Key words: Jiangshui, aroma-producing yeast, screening, enrichment medium, optimization