Study On Isolation, Identification And Application Of Endurable High Temperature And High Alcohol-producing Yeast

Ethanol is an important production and playing an important role in the whole economy. It could be widely applied in the society. The fermentative strains is yeast generally and it product ethanol on the condition of 30～33℃. The temperature on the later stage of fermentation reaches 38℃. In order to sustain the production, the factory have to spend large of energy and cold water. So the study of isolation the strain of yeast which can endurable high temperature and have high productivity is having an important application value.127 strains of yeasts were isolated out successfully from different environments for fuel ethanol-producing. After selecting by four grades, one strain was got which can use maize as fermentation substance to produce maximally ethanol in the high temperature, who was named A27. It is primarily identified as Saccharomyces cerevisiae A27 based on its physiological and biochemical characteristics, and molecular biology identifiable methods. It employed for further studies.The physiological property of the strain was studied. Determine the best temperature and pH value for growth and fermentation and studied the effect of temperature; pH value and inoculation amount during growth and fermentation. Comparison studies of acid and alkali tolerance; osmotic pressure; alcohol and byproducts tolerance between A27 and Angel yeast.Strain A27 grew the best in 36℃and pH of 4.5, whereas its optimum fermentation temperature and pH was 36℃and 4.5, respectively. It was seen that temperature and initial inoculation amount were two important factors in affecting the growth and fermentation of strain A27. It showed good tolerances to various stresses including acid, alkali, and osmotic pressure. Also, strain A27 showed better resistances to high temperature, high concentration alcohol and byproducts.The optimal conditions for high concentration alcohol production were that the concentration of crude corn is 50% (w/v); the inoculation amount of the yeast was 4.5% (v/v); the initial pH value is 4.5; fermentation period was 84 hours. Strain A27 is employed for 10L fermentation under optimal condition, at the end of fermentation, 14.1% (v/v) alcohol was yielded.