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使用Klebsiella pasteurii NG13与修改的酸盐合成酶,从气态中增加了ʟ-谷氨酸的产生

Daisuke Yoshidome^1,2, Keitaro Kuze³, Atsushi Ichiyanagi³

¹Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan. babubabu-babubu@g.ecc.u-tokyo.ac.jp.

Applied microbiology and biotechnology

|December 19, 2025

概括

生物固提供了一个可持续的替代哈伯-博什过程. 研究人员设计了Klebsiella pasteurii来增强葡萄糖衍生L-谷氨酸的产生,通过修改的酸盐合成酶达到2.35g/L.

科学领域:

微生物学和生物技术
生物化学工程生物化学工程
可持续化学可持续化学

背景情况:

生物固是一种可持续的替代能源密集的哈伯-博斯工艺.
之前的研究表明,Klebsiella pasteurii过度产生酸盐合成酶 (CS),酸盐转运体 (CitS) 产生L-氨酸,但主要来自酸盐,而不是葡萄糖.
了解碳流对于优化微生物L-谷氨酸酸生产至关重要.

研究的目的:

为了研究K. pasteurii中L-谷氨酸酸的碳来源,该菌被改造为增强生产.
为了确定限制葡萄糖利用的机制,以合成L-谷氨酸.
设计K. pasteurii以增加葡萄糖衍生L-氨酸的产量.

主要方法:

构造的K. pasteurii菌株产生过多的CS和一个2-氧格酸盐 (2-OG) 载体 (KgtP).
使用葡萄糖和2-OG作为碳来源,研究了碳流.
利用KpCS的结构建模来识别2-OG结合的关键残留物 (H227,V362) 和具有改变抑制常数的创建变体 (KpCS*).
与CitS共同生产的KpCS变种,在持续的葡萄糖养条件下培养.

主要成果:

用KgtP进行工程的K. pasteurii在提供葡萄糖和2-OG时产生了2-OG衍生的L-氨酸.
发现2-Oxoglutarate可以竞争性地抑制CS,转移碳流.
KpCS变体 (H227L,H227Q,V362L) 显示2-OG.抑制常数增加了2.5至12.5倍.
共同生产KpCS变种和CitS的菌株产生了更多的葡萄糖衍生的L-谷氨酸,而不是野生类型.
在连续葡萄糖养下,KpCS (H227Q) +CITS菌株的最大L-谷氨酸酸产量达到2.35g/L.

结论:

酸盐合成酶受抑制的2-oxoglutarate是碳流向L-酸盐的一个关键因素.
工程 CS 变种具有降低 2-OG 灵敏度,可增强葡萄糖衍生 L- 谷氨酸的产生.
这项研究表明了可持续的,与哈伯博什无关的L-谷氨酸酸生产的可行策略.

关键词:

这就是Klebsiella pasteurii.2氧格卢他酸二氧化物酸合成酶的使用方法固定的方法是固定.ʟ-Glutamate 是一种葡萄糖酸盐.

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