《酵母菌的分离提取》-毕业设计（论文）.doc

摘 要 从烟台葡萄果皮以及干红葡萄酒酿造过程不同阶段发酵液中取样分离得到117株酵母菌株，将分离菌株用WL培养基进行鉴别培养，依据菌落色泽初步归类，然后利用26S rDNA D1/D2区域序列分析，并结合其形态学和生理生化特性对21菌株进行分类鉴定,确定了发酵过程中酵母种类及其菌群变化特点。 用杜氏管发酵试验对117株酵母菌株筛选，挑选其中21株发酵力、香味较好的酵母菌株完成抗性和发酵特性评价。有5株发酵力强的菌株进行了模拟酒精发酵试验，结果SL8-1发酵产酒精度最高为10.8，SL9-1发酵产酒精度为10.2高于RC212的产酒度9.2，SS9-2产酒精度与商品酵母RC212相同，SS5-1的产酒精度为7.4， SS1-5酵母菌株发酵产酒精度为0，但香气浓郁。 对筛选的5株优良菌株进行26SrDNA D1/D2区分子鉴定，并与模式菌株序列比对分析确认5株酵母SL8-1,SL9-1,SS9-2,SS1-5,SS5-1均为酿酒酵母，此后以商品酵母为对照进行同步RAPD扩增，比较遗传多样性，结果显示这5株酿酒酵母菌株与发酵时接入的商品种子酵母之间多态条带无明显差异。但两个菌株（SL8-1,SL9-1）的发酵特性，尤其产酒率显著高于商品酵母。 关键词:干红葡萄酒 酵母 发酵特性 评价 鉴定 ABSTRACT 117 natural yeast strains were isolated from Yantai grape fermentation solution of different phase In this paper. Then the strains were classified according to colorful reaction characteristics that showed on the WL medium, and were identified based on the 26S rDNA D1/D2 domain sequence analysis and physiological morphologic characterization, in order to study the changes of the yeasts during the period of fermenting. 21 strains with high fermentation capacity and strong aroma were selected out from 117 strains by Durham tube method. Among them ,5 excellent strains have good fermentation capacity and nice smell. The result of alcohol fermentation showed that alcoholicity of SL8-1 yeast strains was10.8, alcoholicity of SL9-1 yeast strains was10.2, SS9-2 has same alcoholicity with RC212, alcoholicity of SS5-1 yeast strains was7.4, alcoholicity of SS1-5yeast strains was zero ,but it had thick aroma. DNA from the excellent yeast strains then were extracted by micro glass beads and amplified by PCR method. Compare the result sequence with the model strain so as to classify the yeast strains, the result showed that all the 5 strains are saccharomyces. DNA from the excellent yeast strains were analyzed by RAPD-PCR method in order to determine their homology with commercial yeast RC212. We have got that the 5 strains have no difference with the commercial yeast RC212,but the alcoholicity of SL8-1,SL9-1 is better