发酵液中不同分子量的γ-聚谷氨酸的制备及提取
毕业论文关键词：γ-聚谷氨酸；发酵；分子量；超滤；
Preparation and Extraction of the Different Molecular Weight of Gamma Glutamic Acid in the Fermentation Liquid
Abstract: Poly-γ-glutamic acid is a soluble-polymer, which can be produced by various microorganisms through fermentation. Because of it’s advantages like water solubility, bio-degradation, edibility and non-toxicity to human and environment, Poly-γ-glutamic acid and it’s derivatives has wide application in many fields, such as food, cosmetics, medicine, agriculture and so on. This study prepared poly-γ-glutamic acid of different molecular weight with different applications by Bacillus subtilis natto though liquid fermentation. By adjusting the pH of fermentation broth to 2~3 at room temperature, fermented liquid viscosity was reduced and got poly-γ-glutamic acid of different molecular weight at the same time. Combined with subsequent ultra-filtration membrane separation technology, the membrane MWCO is 10000, the operation pressure is 0.05MPa and the permeate flux is 33.4L/hm2, prepared γ-PGA whose molecular weight is above 60000.
Key words: Poly-γ-glutamic acid; Fermentation; Molecular Weight; Ultra-filtration;
目录
1 绪论 1
1.1 前言 1
1.2 γ-PGA理化性质 1
1.3 γ-PGA生产工艺 2
1.3.1 化学合成法 2
1.3.2 提取法 2
1.3.3 酶转化法 2
1.3.4 微生物发酵法 3
1.4 γ-PGA提取工艺 3
1.4.1 发酵液预处理 3
1.4.2 分离纯化 4
1.4.3 γ-PGA产品的获得 4
1.5 γ-PGA应用 4
1.5.1 医药方面 4
1.5.2 食品方面 5
1.5.3 化妆品方面 5
1.5.4 农业方面 5
1.6 研究目的和意义 5
2 材料和方法 6
2.1 材料 6
2.1.1 菌种 6
2.1.2 主要实验试剂 6
2.1.3 主要仪器和设备 6
2.2 方法 7
2.2.1 培养基成分及培养条件 7
2.2.2 pH值对发酵液粘度的影响 7
2.2.3 水解温度对发酵液粘度的影响 7
2.2.4 超声功率对发酵液粘度的影响 8
2.2.5 发酵液粘度测定 8
2.2.6 超滤浓缩 8
2.2.7 SDS-PAGE凝胶电泳法测定分子量 9
3 结果和讨论 12
3.1 pH值对发酵液粘度的影响 12
3.2 水解温度对发酵液粘度的影响 13
3.3 超声波处理对发酵液粘度的影响 14
3.4 SDS-PAGE法测定分子量 15
4 结论 18
4.1 三种因素对γ-PGA相对分子质量的影响 18
4.2 γ-PGA相对分子质量的测定 18
5 展望 19
致谢 20
参考文献 21
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