Breeding Of Saccharomyces Cerevisiae With Hight Emperature And High Gravity By Protoplast Electrofusion Technique

This paper focused on the physiological-biochemical characteristics of the primary strains,the preparing the genetic markers of saccharomyces cerevisiae Ylll ?6 ( a ) ,the condisions of preparing protoplasts,the factors of protoplast electrofusion,the screening of the fiisant,the genetic stability and the fermentation.The saccharomyces cerevisiae Y316 and Ylll have been used as primary strains to obtain haploid cell by isolation and identify their gene types.The optimum factors of UV irradiation mutagenesis was determined: 90s.The arginine auxotrophs were obtained by UV irradiation mutagenesis with Y111-6 ( a ) as the primary strains.This paper studied the optimum factors on the formation and regeneration ofthe protoplasts of the saccharomyces cerevisiae Y316-9 (a) and Y111-62( a ) ,such as the phase of logarithmic growth,the concentration of enzymes andlytic time and discussed the relation of the formation and regeneration of theprotoplasts.The factors of the protoplast electrofusion were determined through orthogonal design test: pulse strength 6kv/cm,pulse time 30 u s and pulse number 5.By using genetic marker as selecting indicator and selecting culture,the fiisant was obtained and the genetic stability and the fermentation of the fusant F79 were studied.The economical benefit of using high temperature fermentation combining with low-temperature cooking process and very high gravity was calculated.