Identification Of Yeast Population Dynamics Of Spontaneous Fermentation Associated With Ice Grapes In Deqin Wine Region, Yunnan And Screening Of Saccharomyces Cerevisiae

The composition of wine yeast populotions,present during spontaneousfermentation of ice grape from Bucun and common grapes from Base,Bucun,Mingyong,Reshuitang,Sinong in Yunnan province was studied. A combination ofbiochemical and molecular techniques was used to identify yeast isolates.Thebiochemical technique is to use WL medium for dividing511yeasts isolated intodifferent types. Molecular techniques involved DNA sequence analysis in the5.8SrDNA-ITS,18SrDNA and26SrDNA D1/D2. The results show that5kinds of yeast,Cryptococcus flavescens，Cryptococcus amylolentus，Hyphopichia pseudoburtonii,Hanseniaspora uvarum，Saccharomyces cerevisiae, present in ice grape pulp.There are9yeasts, Pichia fermentans，Candida oleophile，Hanseniaspora uvarum，Clavisporalusitaniae，Saturnispora，Issatchenkia occidentalis，Issatchenkia terricola，Candidasp.， Saccharomyces cerevisiae,isolated from grapes of Base,Bucun,Mingyong,Reshuitang,Sinong during fermentation.In addition base,these studies all demonstrate asimilar pattern of species evolution during fermentation. In the beginning,non-Saccharomyces present on the surface of the grape appear to dominate the speciesfound in the fermentation.As fermentation progresses, the levels of these yeastsdecrease, while that of Saccharomyces cerevisiae increases. By the end of fermentation,Saccharomyces cerevisiae is the majority of the yeasts found, and often the only yeastisolated.380strains of wild Saccharomyces cerevisiae screened from the fermentation ofice grapes were isolated.In the condition of ethanol concertration(15%),Tartaricacid(6%),sugar concertration(590g/L), KCl(180g/L),S02(600mg/L),6yeasts survive.