摘要：γ-聚谷氨酸（γ-Poly glutamic acid，简称γ-PGA）是一种由微生物合成的胞外水溶性单体氨基酸聚合物，具有优良的保湿性、生物相容性和可降解性。本课题针对γ-PGA在提取纯化环节存在的问题，尝试采用PEG/(NH4)2SO4双水相体系从发酵液中提取γ-PGA。通过改变两相类型、质量配比和体系条件，确定最佳提取工艺，PEG1000质量分数为23%，硫酸铵质量分数为12.5%，发酵液质量分数为10%，发酵液pH值为8，体系温度为25℃时，最大分配系数为2.31，提取率为78.02%。35927
毕业论文关键词：γ-聚谷氨酸；提取；双水相
Extraction of γ-Polyglutamic acid from fermentation liquid by using aqueous two-phase
Abstract γ-Poly glutamic acid(γ-PGA) is a kind of microbe exocellular watersoluble monomer amino acid high polymer. γ-PGA is moisturizing, biocompatibility and biodegradable. Therefore, γ-PGA and its derivatives have been of interest in a broad range of industrial fields such as cosmetics, agriculture, medicine and food. At present the purification and extraction process is the biggest factor affecting the industrialization of γ-PGA. We attempted the PEG/ammonium sulfate two aqueous phases system to extract γ-PGA in fermentation liquid. And the best extraction process was established by changing the type and mass ratio of the two-phase as well as the condition of the system.When PEG1000 mass fraction was 23%, (NH4)2SO4 mass fraction was 12.5%, fermentation liquid mass fraction was 10%.Under this condition, the pH value of the fermentation liquid was 8, the system temperature was 25°C. The maximum of the distribution coefficient K and the extraction rate of Y were respectively. The distribution coefficient K is 2.31, and the extraction rate of Y is 78.02%.
Key words γ-Polyglutamic acid;aqueous two-phase;Extraction
目 录
1绪论 1
1.1 γ-PGA的简介[1～3] 1
1.2 γ-PGA的性质 1
1.2.1 吸水特性 1
1.2.2 生物可降解性 2
1.2.3 γ-PGA的水解特性 2
1.3 γ-PGA的应用[21] 2
1.3.1 γ-PGA在农业中的应用 2
1.3.2 γ-PGA在日用品中的应用 3
1.3.3 γ-PGA在医药中的应用 3
1.3.5 γ-PGA在食品工业中的应用 4
1.4 国内外发酵产γ-PGA的提取工艺研究现状[7～10] 4
1.4.1发酵液预处理 5
1.4.2分离纯化 5
1.5 研究目的和意义 6
1.5.1 研究目的 6
1.5.2 研究意义 6
1.5.3 研究任务 6
2.材料和方法 7
2.1材料 7
2.1.1 菌种 7
2.1.2 主要实验试剂 7
2.1.3 主要仪器和设备 7
2.2 发酵液的制备 8
2.2.1 培养基成分及培养条件 8
2.2.2 发酵液预处理 9
2.3 实验方案 9
2.3.1 实验原理 9
2.3.2 实验方案 9
3 结果与讨论 10
3.1不同质量分数的硫酸铵和PEG对γ-PGA的水解的影响及吸收峰的影响。 10
3.2硫酸铵和PEG自身对吸收峰的影响 10
3.3标准曲线的绘制 10
3.4单因素实验的条件优化 11
3.4.1 PEG质量分数对分配系数及提取率的影响 11
3.4.2 硫酸铵质量分数对分配系数及提取率的影响 12 双水相体系从发酵液中提取γ-聚谷氨酸:http://www.751com.cn/shengwu/lunwen_34144.html