The Screening And Appilication Of Indigenous Saccharomyces Cerevisiae From Vitis Davidii

Saccharomyces cerevisiae play a crucial role in the wine making process as well as grape variety.At present,almost all of the yeast strains used in the fermentation of our wineries are commercial yeasts that imported from foreign countries.In China,the breeding of indigenous yeast is still in its infancy.Yeast strains those can be applied to the production of wine industry which has been screened and breeded by our own country is also insufficient.Based on the target of development and utilization of the important Chinese wild grape resources,Vitis davidii,this paper isolated and identificate the wild yeast from the main cultivated area and the main cultivated varieties or types.After identification,the basic characteristics of ten S.cerevisiae strains were evaluated.And then,the impact on the quality of V.davidii wine was detected.According to these results the excellent indigenous yeast strains suitable for brewing V.davidii wine were screened out.The main findings of this research are as follows:1,In this research,405 strains of yeast were separated from peel surface and the four different periods of spontaneous fermentation of four different grape varieties/types in two vineyards.These strains of yeast were divided into 13 different species by the morphological classification of WL medium and 26S sequence alignment in D1/D2 region.They were S.cerevisiae,Saccharomycopsis vini,Hanseniaspora uvarum,Hanseniaspora opuntiae,Hanseniaspera guilliermondii,Hanseniaspora occidentalis,Issatchenkia terricola,Candida zemplinina,Candida railenensis,Zygoascus meyerae,Debaryomyce shansenii,Sporidiobolus pararoseus and Candida sp.A1179.The highest frequency of non-Saccharomyces isolated from the various periods of fermentation are H.uvarum and H.opuntiae.In this study,63 strains of S.cerevisiae were isolated and divided them into?,?,?,?and?types by Interdelta sequence analysis.2,We studied the fermentation characteristics of 10 indigenous S.cerevisiae and 2commercial S.cerevisiae as controls.Among them,the LD1015,HME11,LD22,HXD20 has high glucose tolerance;the HME11,LE20,LD22,HXD29 has higher alcohol tolerance than others;the LE7,LE20,HXB48,HXD21,LE28 strains are more resistant to SO₂;and compared to other strains the LD1015,HME11,LE28 has more tolerant to low pH;the results showed that the four strains,LD22,LE28,HXD29 and LE20,with obvious yeast addiction had lower ability to produce H₂S;in the triple M fermentation experiment,LD1015,LE28,LD22 may have excellent characteristics of alcoholic fermentation,the basic fermentation characteristics of all of these strains are different.3,This study found that the effects of S.cerevisiae on aroma substances in the wine of Vitis davidii were different.From wine sensory evaluation,we found the HXD20,HXD29,LE17 and LE28 are more excellent.The ester substance is the main component of the aroma substance of the wine,followed by the alcohol.1-Octen-3-ol,ethyl acetate,isoamyl acetate,ethyl caproate and damascenone etc are the most important contribution to the aroma of the wine of Vitis davidii.Based on these results,we preliminarily definited the characteristics of the Vitis davidii wine aroma.The correlation coefficient clustering analysis of OAV values of different yeast wine samples showed that:The LD1015 is the most unique among the 10 tested native yeasts;LE28,HXD29 and LD22 are the closest to the commercial yeast RC212,which is consistent with the aroma characteristics of the wine and the other six yeasts are consistent.