Screening, Identification And Fermentation Characteristics Of Chinese Rice Wine Yeast Strain And Haploid

Rice wine is our traditional brewing food, which is famous for its unique flavor, plenty nutrients and higher health benefits. It is brewed by using grains as the main raw material, with the combined effect of a variety of microorganisms in Jiuyao, the wheat starter or rice-koji. Saccharomyces cerevisiae, as the key microorganism, played a leading role in the fermentation. In the fermentation process of rice wine, yeast cells are subjected to stress of various environmental factors, such as temperature, osmotic pressure, pH, ethanol concentration. When stress conditions exceed the physiological limits of the cell, it will inhibit yeast cell growth and ethanol fennentation efficiency. Therefore, it is essential for rice wine fennentation industry to select excellent rice wine yeast strains with improved stress-tolerant capbility.52strains were isolated from the wheat starter, fennenting mash of rice wine and jiuyao; through the experiments of resistance to ethanol and osmotic pressure,11excellent strains were obtained by primary screening; then, the second round of screening based on the characteristics of the rice wine fermentation process, using high-sugar and high-acid environment,4strains were obtained;The morphological, physiological and biochemical tests indicated that screened four strains could be classified as belonging to Saccharomyces cerevisiae; ITS sequences and pulsed-field gel electrophoresis analysis reenforced that the four strains was belonged to Saccharomyces cerevisiae.4rice wine yeast strains fermentation test results showed that the fermentation ability of the strains F-18and F-19was better than strains J-16and J-26in fermentation ability, rice wine quality, color and other parameters; Comparison with gongchang strain, F-18strain was almost same to gongchang strain on the amount of ethanol production, but the wine producing rate, total acid, ammonia nitrogen and non-sugar solids was higher than gongchang strain, resulting in the increase of the color and taste of the rice wine; In addition, we also obtained the Saccharomyces cerevisiae strain J-16and J-26with lower alcohol yield, providing the basis for the low alcohol production of rice wine.Spore-forming culture of yellow rice wine yeast was carried out to obtain its genetic breeding haploid parent, and followed by the tolerance of haploid yeast in stress conditions tests. We obtained two resistance excellent haploid strains, D-2and D-3. Fermentation test results showed that under the same fermentation conditions, D-2and D-3had higher capacity of sugar utilization, less ethanol production, higher acid production and the higher alcohol yield fermentation characteristics, which laid the foundation for the genetic breeding of rice wine yeast.