Comparison Of Urea Production And Stress Tolerance And Identification Of Saccharomyces Cerevisiae Rice Wine Strains

The rice wine (Huangjiu) is Chinese traditional brewing wine, which is mainly brewed by using grains as materials and effect of varieties of microorganisms in the wheat koji. As the key microorganism, Saccharomyces cerevisiae play a leading role in the fermentation. Therefore, it is important for rice wine industry to select excellent rice wine yeast strains with excellent fermentation capbility.We analysed the capacity of producing urea of 8 strains, through the experiments of using arginine and urea as the sole nitrogen source. Finally, we selected lower urea production strains AW001, MT, YJSHl by analyzing the growth and metabolic abilities of strains.In order to obtain strains with better stress tolerance, the strain screening was carried out based on using high-ethanol, high-sugar, high-osmotic and high-acid environment. Finally, we obtained strains AW001, J-16-2, MT with higher ability of tolerance to ethanol, strains BJ, N85, MT with higher ability of tolerance to sugar, strains AW001 with high ability of fermenting sugar, strains J-16-2, MT, YJSH1 with higher ability of tolerance to osmotic, but have little difference in the terms of lactic acid.Laboratory simulation rice wine fermentation test results showed that the strain MT was better in alcohol fermentation ability, the strain AW001 has the most in sugar concentration, but there is little difference in content of amino acid nitrogen and urea nitrogen. In terms of volatile component, especially in the concentration of high alcohol, strains AW001, MT, N85 were weaker than other strains. Therefore, we also obtained the Saccharomyces cerevisiae strains with lower high alcohol yield, providing the basis for the low high alcohol production of rice wine industry.The morphological, physiological and biochemical tests indicated that three strains could be classified as Saccharomyces cerevisiae species; ITS sequences analysis reenforced that the three strains was belonged to Saccharomyces cerevisiae.From the above, this experiment with breeding excellent rice wine yeast strains as the goal by screening the strains of lower urea production, high tolerance to external stress factors, followed by physiological and biochemical and molecular identification. Finally, combined with laboratory simulation rice wine fermentation, yeast strains AW001, MT were screened in line with the target.