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Screening And Identify Of Special Yeast For Pear Wine And Construction Of Engineering Bacterium

Posted on:2013-10-18Degree:MasterType:Thesis
Country:ChinaCandidate:L JinFull Text:PDF
GTID:2231330371987815Subject:Food Science
Abstract/Summary:PDF Full Text Request
Used pear peel and pear orchard soil as the separation source, theexperiment separated and filtered perry yeasts, and used yeasts with goodfermentation performance and aroma producing performance as parents. Theexcellent strains are suitable for the production of perry, which has fasterpropagation speed, stronger fermentation capacity and wine-producing capacitythan the original strains by protoplast fusion technique.Through enrichment culture and separation of yeast, primary screening byTTC tablet, second screening by Du fermentation tube and third screening byflask fermentation, the experiment got the strain YDJ05which has optimalfermentation performance and the other strain YS03which has optimal aromaproducing performance. They can use as the original strain for protoplast fusion.The result showed that the strain YDJ05made wine production rate reach8.8%in7days, then the content of residual sugar was low, which had strongfermentation capacity and wine-producing capacity in pear juice. By26SrDNAthe D1/D2sequence analysis, the strains YDJ05was identified asSaccharomyces cerevisiae, named Saccharomyces cerevisiae YDJ05. By sensoryevaluation, the strain YS03has optimal aroma producing capacity, and thecontent of total ester reached0.38g/L on the sixth fermented day with thestrongest aroma. By26SrDNA the D1/D2sequence analysis, the strain YS03was identified as Issatchenkia orientalis, named Issatchenkia orientalis YS03.They can be used independently.Using Saccharomyces cerevisiae YDJ05as parent strain X, arginineauxotrophic strain G1was gotten by EMS mutagenesis of Issatchenkia orientalisYS03as parent strain Y. The experiment used snail enzyme solution to merge the parent strains at35℃,100min. The result got the optimal formation rate andregeneration rate of protoplast, which reached93.6%,94.2%,27.8%,31.6%respectively. The protoplast of parent strain X was heated to inactivate by60℃water bath, then the inactivation time was determined14minutes. UsingPEG-6000as promote financial agent, the protoplast of parent strain X&Y weremerged, and DJ01~DJ06six fusants were gotten. Among them, the producingalcohol and aroma producing rate of DJ02reached9.87%,0.37g/L respectively.By26SrDNA the D1/D2sequence analysis, the fusant DJ02was identified asSaccharomyces cerevisiae, named Saccharomyces cerevisiae DJ02. The resultshowed that the fusant DJ02was a yeast strain that was appropriate for thebrewing of perry, which has advantage of the parents at the same time.
Keywords/Search Tags:pear wine, yeast, screening, protoplast fusion, identify
PDF Full Text Request
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