酸合成酶变体改善了Escherichia coli中乙烯基-CoA衍生的3-基酸的产量
Hemshikha Rajpurohit1, Mark A Eiteman2,3
1School of Chemical, Materials and Biomedical Engineering, Athens, GA, USA.
Microbial cell factories
|June 12, 2024
概括
用修改的酸盐合成酶 (gltA) 酶改造的大肠杆菌显著增加了 (R) -3-基酸盐 (3-HB) 的产量. 这种方法增强了微生物生产有价值的乙-CoA衍生化合物.
科学领域:
- 生物技术是生物技术.
- 代谢工程是代谢工程.
- 合成生物学 合成生物学
背景情况:
- 工业和医疗化合物的前体 (R) -3-基酸盐 (3-HB) 的微生物生产受限于对乙-CoA.竞争的途径.
- 在大肠杆菌中,酸盐合成酶 (gltA) 将超过60%的乙-甲酸导向三碳酸循环,阻碍了3-HB合成.
研究的目的:
- 通过向酶替代,通过减少但不消除酸盐合成酶活性来增强3-HB产量.
- 调查改性酸盐合成酶对乙-CoA流量和微生物3-HB的产生的影响.
主要方法:
- 产生并选了五种大肠杆菌GltA变体以通过异质表达酶 (phaA) 和乙乙-CoA减少酶 (phaB) 来产生3-HB.
- 评估的3-HB产量,pyruvate积累和乙-CoA转移在摇瓶和受控批量培养中.
- 使用gltA[A267T]变种在酸盐缺乏的重复批次工艺中优化生产.
主要成果:
- 与野生型大肠杆菌相比,四种GltA变异表明3-HB产量增加了近5倍.
- 在批量研究中,GltA[A267T]变异实现了4.9g/L的3-HB标位.
- 在重复的批次发酵中,工程菌株产生了15.9g/L的3-HB (有效21.3g/L),从葡萄糖中产出的产量为0.16g/g.
结论:
- 在酸盐合成酶 (gltA) 中的有针对性的替代物有效地将乙-CoA 流转向大肠杆菌中的3-HB 生产.
- 这一策略提供了一种可行的方法来提高各种乙-CoA衍生生物化学品的产量.
- 通过增强路径酶的基质亲和力来进一步优化,可以改善3-HB的生产并减少副产品.
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