Study on Ethanol Tolerance of Saccharomyces cerevisiae X330 under Very High Gravity Medium
酿酒酵母X330高浓度发酵时耐酒精性能的初步研究

The impacts of osmoprotectants and nutrient components on both ethanol tolerance of Saccharomyces cerevisiae X330 and its ethanol fermentability were investigated when high gravity synthetic medium were used. The results indicate that nutrient limitation plays important role in the ethanol tolerance of Saccharomyces cerevisiae. When the nutritional requirements of Saccharomyces cerevisiae are satisfied, its ethanol tolerance increases, especially at high sugar concentrations. The effect of the individual nutrient component in the PYN medium on ethanol tolerance is different, which is yeast extract > peptone > magnesium sulfate > vitamin C = potassium phosphate > calcium chloride = ammonium sulfate. Osmoprotectants ( such as glycine and proline ) are effective in improving the ethanol tolerance of Saccharomyces cerevisiae X330, and the optimum concentrations of 20 mmol/L glycine and 10 mmol/L proline were obtained experimentally while glycine exerted a stronger enhancing effect than proline. After 3 h of exposure to 18% (V/V) ethanol at 30 degrees C, 57.1% and 50.0% remained viable for the cells grown in glycine-added and proline-added medium respectively.