γ-聚谷氨酸的分离与纯化

摘要γ-聚谷氨酸(γ–PGA)是一种天然的由微生物发酵产生的水溶性多聚氨基酸，早在上个世纪 20年代在炭疽芽孢杆菌的细胞荚膜中被发现。γ–PGA是由γ-酰胺键结合 L-谷氨酸和D-谷氨酸形成的一种多肽分子，是通过微生物合成的一种高分子量聚合物。由于它是一种有良好吸水性、生物可降解性和生物相容性的生物大分子，在生产生活的很多领域都有它的应用。目前，利用纳豆芽孢杆菌微生物发酵法虽然是生产的主流，但是在合成聚谷氨酸过程中其降解也同时被启动。为了克服这一问题并进一步达到 γ-PGA的批量生产目的，本论文首先通过菌种筛选，挑选出生产γ-PGA产量高的菌株。再通过对复合碳源、环境 pH值以及盐浓度等影响γ-PGA发酵生产的因素进行系统研究，得到最佳的培养基配方和较适的培养条件以便将γ-PGA 的产量提到最大化。并最后对所生产的 γ-PGA产物进行分离和提纯。 48049
毕业论文关键词 γ-聚谷氨酸纳豆芽孢杆菌微生物发酵分离纯化 
Title Isolation and purification of γ-poly glutamic acid Abstract γ-PGA is natural and water soluble polymers of glutamic acid, a kind of polypeptide molecule derived from microorganism fermentation and synthesized by forming gamma-amide bond of L-, and D-glutamic acid, and found in the capsule of anthrax bacillus cells as early as 1913. Due to its good water imbibition, biocompatibility and biodegradability, the microbial synthesis of gamma- PGA, a kind of high molecular weight polymer, are widely used in various industries including food, drug and environmental protection. At present, despite Bacillus natto microorganism fermentation is the mainstream methods to produce gamma - PGA，however, the major problem of this processes is the simultaneous initiation of synthesis and degradation process. To overcome this problem, we firstly selected Bacillus natto strain with high protein synthetase activity, and secondly obtained the optimal components of culture media and optimal culture conditions by analysis the key factors effect on fermentation, such as Compounded Carbohydrate, Environmental pH value, and Salting Concentration. Finally, we also isolated and purified the γ-PGA from the gamma - PGA crude products derived from thus optimal conditions.
Keywords γ-PGA Bacillus natto Microbial fermentation Isolation Purification 

中文摘要 Ⅰ

Abstract .. Ⅱ

1.引言 6

1.1 纳豆芽孢杆菌 6

1.2 聚谷氨酸 . 6

1.2.1聚谷氨酸的化学结构 6

1.2.2聚谷氨酸的立体化学结构 . 7

1.2.3 聚谷氨酸的生物合成 .. 8

1.2.4 聚谷氨酸的提取 . 8

1.2.5 聚谷氨酸的应用 . 9

1.3 课题研究意义 .. 10

2 实验方法 . 11

2.1 菌株的筛选 . 11

2.2 聚谷氨酸的发酵生产 12

2.2.1实验试剂 12

2.2.2实验仪器 13

2.2.3培养基和培养条件 .. 14

2.2.4最佳发酵培养基成分和培养条件优化实验 . 15

2.3 发酵液的处理 15

2.4γ-聚谷氨酸的提取 . 15

2.5 分析方法 .. 16

2.5.1 SDS-PAGE 电泳 16

2.5.2谷氨酸钠的紫外可见光分光光度检测方法 . 17

3.结果与分析 18 γ-聚谷氨酸的分离与纯化 :http://www.youerw.com/shengwu/lunwen_50389.html