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Two Recombinant Saccharomyces Cerevisiae Fermentation And A Recombinant Saccharomyces Cerevisiae Is Initially Built

Posted on:2008-02-07Degree:MasterType:Thesis
Country:ChinaCandidate:J K LiuFull Text:PDF
GTID:2190360212488105Subject:Microbiology
Abstract/Summary:PDF Full Text Request
The intense global and domestic's energy situation strengthen the demand of making fuel ethanol from cheap and ubiquitous biomass. High cost is the main factor of blocking the development of production of ethanol from lignocellulose's hydrolysate. One solution is to ferment the xylose exist in the hydrolysate into ethanol which can be not fermented by traditional industrial S. cerevisiae before. So it's necessary to establish a metabolic pathway that can ferment yeast in the industrial S. cerevisiae. The article's preface also summarized the general situation of the recombinant S. cerevisiae that can ferment xylose, and the meaning and the objection of this experiment as well.In this article two strains of recombinant S. cerevisiae was fermented by xylose, glucose and mixture of these two sugers. The fermentation of YS58-1 showed that the recombinant strains can't ferment xylose into ethanol. When glucose exist in the fermentation culture, the utilization of xylose could reached to 50%. However the strain couldn't ferment xylose to ethanol either. It is assumed that the xylose was mainly transformed into xylitol. The fermentation of YS58-12 showed that the strains can fermented a small amount of ethanol, but it can be resulted from the unwanted fermentable sugar existed in the fermentation culture from yeast extraction.Candida shehatae xyl1 gene was amplified by PCR, and cloned into the expression vector pACT2 to produce the recombinant expression vector pACT2-xyl1. The vector's sequence preference of Escherichia coli host was also discussed. The sequence with xyl1 gene ADH promoter and terminator was also cloned by PCR. S. cerevisiae xyl2 gene was also cloned by PCR, and inserted into the expression vector pDR195 to make the recombinant expression vector pDR195-xyl2. Another vector called pDY was established by part of pDR195 and part of pYES2 to sequence the unknown key sequence of pDR195.
Keywords/Search Tags:xyl1, xyl2, ethanol, xylose, glucose, S. cerevisiae
PDF Full Text Request
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