Engineering of CmpLs enhances L-glutamate production of <i>Corynebacterium glutamicum</i>.

Xingtao ZUO; Shasha ZHONG; Ningyun CAI; Tuo SHI; Zhidan ZHANG; Yuantao LIU; Jiao LIU; Depei WANG; Jiuzhou CHEN; Ping ZHENG

Return

Engineering of CmpLs enhances L-glutamate production of Corynebacterium glutamicum.

Author: Xingtao ZUO ¹ ; Shasha ZHONG ¹ ; Ningyun CAI ¹ ; Tuo SHI ² ; Zhidan ZHANG ² ; Yuantao LIU ³ ; Jiao LIU ² ; Depei WANG ¹ ; Jiuzhou CHEN ² ; Ping ZHENG ²
Author Information

1. School of Biological Engineering, Tianjin University of Science and Technology, Tianjin 300457, China.
2. Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China.
3. Hulunbeier Northeast Fufeng Biotechnologies Co., Ltd., Hulunbuir 162650, Inner Mongolia, China.
Publication Type:Journal Article
Keywords: Corynebacterium glutamicum; L-glutamate; biosynthesis; mycolic acid; transporter
MeSH: Corynebacterium glutamicum/genetics*; Glutamic Acid/biosynthesis*; Fermentation; Metabolic Engineering; Bacterial Proteins/metabolism*; Bioreactors/microbiology*; Gene Knockout Techniques
From: Chinese Journal of Biotechnology 2025;41(1):271-287
CountryChina
Language:Chinese
Abstract: The efficient production of L-glutamate is dependent on the product's rapid efflux, hence researchers have recently concentrated on artificially modifying its transport system and cell membrane wall structure. Considering the unique composition and structure of the cell wall of Corynebacterium glutamicum, we investigated the effects of CmpLs on L-glutamate synthesis and transport in SCgGC7, a constitutive L-glutamate efflux strain. First, the knockout strains of CmpLs were constructed, and it was confirmed that the deletion of CmpL1 and CmpL4 significantly improved the performance of L-glutamate producers. Next, temperature-sensitive L-glutamate fermentation with the CmpL1 and CmpL4 knockout strains were carried out in 5 L bioreactors, where the knockout strains showcased temperature-sensitive characteristics and enhanced capacities for L-glutamate production under high temperatures. Notably, the CmpL1 knockout strain outperformed the control strain in terms of L-glutamate production, showing production and yield increases of 69.2% and 55.3%, respectively. Finally, the intracellular and extracellular metabolites collected at the end of the fermentation process were analyzed. The modification of CmpLs greatly improved the L-glutamate excretion and metabolic flux for both L-glutamate production and transport. Additionally, the CmpL1 knockout strain showed decreased accumulation of downstream metabolites of L-glutamate and intermediate metabolites of tricarboxylic acid (TCA) cycle, which were consistent with its high L-glutamate biosynthesis capacity. In addition to offering an ideal target for improving the stability and performance of the industrial strains for L-glutamate production, the functional complementarity and redundancy of CmpLs provide a novel target and method for improving the transport of other metabolites by modification of the cell membrane and cell wall structures in C. glutamicum.