胁迫条件对酿酒酵母生物合成海藻糖的影响
时间:2019-01-16 20:06 来源:毕业论文 作者:毕业论文 点击:次
| 摘要：海藻糖是一种非还原性双糖，其结构稳定，除了作为储存碳源之外，还能保护生物体内的蛋白质、核酸等大分子结构不受外界恶劣环境的损害，同时对体外的大分子也有一定的稳定作用。但海藻糖作为一种应激代谢物，只有在营养缺乏、生长受限等情况下才开始积累，常规使用的酵母菌发酵生产工艺，其海藻糖产量并不十分理想，因此本研究通过选用摇瓶发酵，以马铃薯葡萄糖液为培养基，在28℃、200rpm的条件基础上，采用改变培养温度、pH、渗透压、加入有毒物质及金属离子等方法，以提高海藻糖积累量；再对以上条件进行综合考察。结果显示：改变温度、pH、渗透压及加入Mg盐后，海藻糖积累量提高了1.20倍、1.40倍、1.14倍、1.22倍；通过正交实验，得出如下方案：温度为42.5℃、pH为10.5、NaCl含量为0.35mol/L、Mg2+含量为0.5mol/L。此时海藻糖积累量提高了1.27倍，相比于单一胁迫条件其效果并非最佳，故并非条件越恶劣，海藻糖积累量就越多。32829 毕业论文关键词：海藻糖；酿酒酵母；胁迫条件；发酵 Stress conditions on Saccharomyces cerevisiae biosynthesis of trehalose Abstract：Trehalose is a non-reducing disaccharide, the structure is stable, in addition to being a carbon source storage, but also to protect the living body of proteins, nucleic acids and other macromolecules structure is not compromised external harsh environment, while the in vitro macromolecular there is a certain stability. But trehalose as a stress metabolite, only in nutritional deficiencies, growth retardation and other cases began to accumulate, yeast fermentation processes conventionally used, the trehalose yield is not very satisfactory, so this study by choosing shake bottle fermented potato dextrose solution as medium, the conditions on the basis of 28℃、200rpm, by changing the culture temperature, pH, osmolality, added toxic substances and metal ions and other methods to improve the accumulation of trehalose; and then have a comprehensive study of the above conditions. The results show: changes in temperature, pH, osmolality and Mg salt added, the accumulation of trehalose improved 1.20 times, 1.40 times, 1.14 times, 1.22 times; By orthogonal experiments, have the following scheme: temperature of 42.5 ℃, pH of 10.5, NaCl content of 0.35mol / L, Mg2+ content of 0.5mol / L. At this accumulation of trehalose increase by 1.27 times, compared to single stress effect is not the best, it is not the more severe conditions, the greater the accumulation of trehalose. Key Words：trehalose；S.cerevisiae；stress；fermentation 目 录 1 绪论 1 1.1 本课题的国内外研究进展 1 1.2 本课题的研究内容、目的及意义 2 2 材料与方法 4 2.1 实验材料 4 2.1.1 菌株及培养基 4 2.1.2 实验试剂 4 2.1.3 实验设备 5 2.2 分析方法 5 2.2.1 菌液浓度测定方法 5 2.2.2 海藻糖含量测定方法 5 2.3 实验方法 7 2.3.1 酵母菌生长曲线及海藻糖含量变化的测定 7 2.3.2 胁迫条件下海藻糖含量的测定 7 3 结果与讨论 10 3.1 酵母菌生长曲线及海藻糖含量变化曲线测定 10 3.2 胁迫条件对酵母菌积累海藻糖的影响 10 3.2.1 温度对海藻糖积累的影响 10 3.2.2 pH对海藻糖积累的影响 11 3.2.3 乙醇对海藻糖积累的影响 12 (责任编辑：qin) |