The Isolation And Identification Of Yeast During The Spontaneous Fermentation Of Grape And Quality Wine Yeast Strains Selection

Yeast is the main microbes in Wine Making, and it can directly affect the quality and style of wine. The yeasts which from grape original region can present variety characteristics and regional characteristics. Northeast China is one of the main wine production area. Therefore, it's important to breed the quality yeast which is suitable for local grape feature. The aim of this study is to develop the wine yeast resources of Northeast China, which by virtue of geographical condition and ecological condition of Northeast China.In this study, yeasts were isolated from 4 different grape varieties in the city of Song Yuan: 'Shuang Hong','Shuang You','Cabernet Sauvignon','Seibel Noir', these yeasts were identified primarily by Wallerstein Laboratory Nutrient Agar (WL Agar); Then yeasts were further identified by 5.8S rDNA-ITS RFLP analysis; Based on this, all of the Saccharomyces cerevisiae used to select quality wine yeast.The main results are as follows:1.240 wine related yeasts were isolated from the spontaneous fermentation of 4 different grape varieties. The result indicates that there are 6 WL culture types of these yeasts.2. According to the 5.8S-ITS RFLP analysis,5 kinds of yeasts were found in the fermentation broth of these 4 grape varieties:Hanseniaspora uvarum, Saccharomyces cerevisiae, Rhodutorula glutinis, Issatchenkia terricola, Candida sorbosa.3. This work showed that WL Agar was useful in most part of wine yeast identification, which during the spontaneous fermentation of grap. And the WL Agar was effective for the identification of S. cerevisiae and the reliability is 100%.4. The trend of the proportion of the flora in the spontaneous fermentation of Amur grape change is similar to which in Vitis vinifera and Europe America hybrid Vitis. H. uvarum plays a dominant role during the earlier spontaneous fermentation; The flora turn to be complex in the middle spontaneous fermentation, which contain 5 classes yeast species; S.cerevisiae plays a dominant role in the spontaneous fermentation anaphase.5. After 3 steps selection, the quality wine yeast strain named SYC1 and HSB20, which with quick start fermentation had received. These 2 wild yeasts had the high ability of produce alcohol, and its alcohol fermentation rate was obviously higher than active dry yeast. Meanwhile, this study showed that there were quality wild wine yeasts during the spontaneous fermentation of local grape.