在shikimic酸的生物合成期间的芳平衡
D R Knop1, K M Draths, S S Chandran
1The Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA.
Journal of the American Chemical Society
|October 18, 2001
概括
改善微生物生产的shikimic酸,一个有价值的合成前体,需要尽量减少副产品的形成. 研究人员确定,酸副产品的形成源于酸的运输和在大肠杆菌中的平衡.
科学领域:
- 生物技术是生物技术.
- 代谢工程是代谢工程.
- 微生物合成 微生物合成
背景情况:
- 石基胺酸是化学合成的关键芳化合物,但其由植物衍生的分离成本昂贵且有限.
- 已开发出重组的大肠杆菌菌株用于从葡萄糖中生物合成什基米酸,但产量往往因显著的副产品形成而减少,主要是酸和3-脱什基米酸.
- 了解副产品形成背后的机制对于优化石胺酸生产至关重要.
研究的目的:
- 为了阐明微生物shikimic酸生物合成期间酸形成的机制.
- 确定减少酸和改善合成石基胺酸的整体产量和纯度的策略.
- 为了提高大肠杆菌作为细胞工厂的效率,用于生产石基胺酸.
主要方法:
- 使用的复合大肠杆菌菌株 (大肠杆菌SP1.1/pKD12.138和大肠杆菌SP1.1/pSC5.214A) 经过工程设计,用于合成什基米酸.
- 通过分析不同条件下的石基酸盐,酸盐和脱水石基酸盐的摩尔比率来研究副产品的形成.
- 进行了一种不能进行 de novo shikimic acid 合成的菌株的实验,以研究外源的shikimic acid 转化为副产品.
- 操纵了什基马酸运输,以评估其对酸形成的影响.
主要成果:
- 大肠杆菌对石基胺酸的典型合成产生了一种含有大量酸和3-脱石基胺酸的混合物.
- 实验表明,酸的形成与最初合成的酸的微生物催化平衡有关,可能涉及细胞质运输.
- 抑制大肠杆菌SP1.1/pKD12.138中石基酸运输显著增加了石基酸标位,达到52g/L,纯度提高 (14:1.0:3.0石基酸/酸/脱水石基酸比率).
结论:
- 在微生物石墨酸生物合成过程中,酸副产品的形成主要是由于一个涉及石墨酸运输和随后细胞内的代谢反应的平衡过程.
- 控制或抑制shikimate运输的工程策略可以大大提高生物合成的shikimic acid的产量和纯度.
- 这项研究为优化代谢工程策略提供了关键的机制见解,以改善使用大肠杆菌的石基米酸的工业生产.
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