Physilogy And Ethanol Fermentation Influence Of GAL3 Knockout In Yeast

GAL3 gene exists extensively in eukaryotes. Yeast is also the eukaryotes. The genes of humans and other animals have relevance with the yeast. It can be a reference as the function of human genome. Yeast is a single-celled eukaryotes. It has a lot of advantages, for example, the short life cycle, easy cultivation, and so on.The history of mankind is also a wine brewing history. Today’s society has long been unable to separate the wine and alcohol. The alcohol plays a important role in people’s daily life, and at the same time, it’s significant for the pharmaceutical, chemical, food industries and so on. Saccharomyces cerevisiae gene function and fermentation performance has been the focus of research and hotspots.GAL3 gene is an induction and signal transduction gene in galactose metabolism of saccharomyces cerevisiae. In galactosyl medium as the sole carbon source, with the help of ATP, GALS protein can combine with GAL80 which is a inhibitory factor of yeast metabolism of galactose and then make the transcriptional activation factor GAL4 transcription, and yeast galactose metabolism can run smoothly. This article is based on MF1015 strains, using the haploid system and carries on the homologous recombination. Then knock out the Haploid strains and hybridization, forming a diploid, and gain a GAL3 mutant strains. Researching the mutant’s physiological characteristics and the effect of saccharomyces cerevisiae fermentation to produce ethanol. The results of the study are as follows:Building the MF1015 strains of type a and type a haploid, Synthesis of GAL3 knockout components, and successfully into two haploid. By G418 resistance filtering, we gain a haploid mutant strain. Two haploid mutant strains of type a and type a join YPD medium and let them natural mating and become a diploid. At last, we gain a mutant strain MF1015-AGAL3. Then turn pSH65 expression plasmid into the mutant strain. Use the galactose to induce pSH65 expression plasmid, remove G418 resistance genes, and then hand from generation to generation until pSH65 expression plasmid lost. At last, we gain the mutant strain that we need. Under the same conditions, determine the basic cell physiological status and ethanol fermentation performance. Mutant strains compared with wild-type strains, its growth rate became slow, Cell morphology transformed from circular to elliptic, the cell’s respiration reducing, the degree of resistance to acetic acid increased significantly, Ethanol resistance, heat resistance, low temperature resistance are slightly lower. At the same time, the glucose, sucrose, cottonseed sugar, lactose and galactose and so on, using ability of sugar is also reduced. Wild type strain of galactose utilization delayed 6 hours or so, knockouting GAL3 Gene’s mutant bacteria delay 2-5 days, and resistance to galactose resistance is reduced. In the molasses fermentation experiments, Wild type and mutant strain ferment to produce maximum concentration of ethanol, respectively (13.13±0.18)% and (12.76± 0.17)%. In wild type, the utilization of sugar is higher 1.6%. Wild type produced ethanol concentration (14.05±0.28)%, mutant (13.02±0.58)%. The results show that GALS mutation of saccharomyces cerevisiae has a great influence on physical characteristics and ethanol fermentation.