Screening, Identification and Fermentation Process Optimization of Ester-producing Yeast in the Vineyard Soil

Since ester-producing yeast is able to produce esters during the fermentation process, it is widely used in the wine and condiment brewing industry. In this study, a strain of high-yield ester yeast was screened and identified from the vineyard soil of the Sixth Division in Xinjiang province through primary screening and secondary screening, and it was identified as Clavispora lusitaniae by physiological and biochemical identification and molecular biology experiments. Through single factor experiment and response surface method, the optimal fermentation medium composition and fermentation conditions of the yeast were determined: soluble starch 9.35 g/L, peptone 3.02 g/L, potassium di-hydrogen phosphate 0.3 g/L, acetic acid 0.5%, ethanol 3%, temperature 35 °C, inoculation volume 2%, rotation speed 150 r/min. Under the optimal culture conditions, the fermentation yield of this large yeast system was 3.56 g/L. This study provided a new source of fermentation microorganisms and technical reference for the improvement of the content of esters in alcohol and condiments.