State Key Laboratory of Biobased Material and Green Papermaking (LBMP), Qilu University of Technology), Jinan, 250353, Shandong, People's Republic of China.
School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, People's Republic of China.
Amino Acids. 2020 Oct;52(10):1363-1374. doi: 10.1007/s00726-020-02893-6. Epub 2020 Oct 6.
Corynebacterium glutamicum has a long and successful history in the biotechnological production of L-lysine. Besides the adjustment of metabolic pathways, intracellular and extracellular transport systems are critical for the cellular metabolism of L-lysine or its by-products. Here, three amino acid transmembrane transporters, namely, GluE, BrnE/BrnF, and LysP, which are widely present in C. glutamicum strains, were each investigated by gene knockout. In comparison with that in the wild-type strain, the yield of L-lysine increased by 9.0%, 12.3%, and 10.0% after the deletion of the gluE, brnE/brnF, and lysP genes, respectively, in C. glutamicum 23,604. Moreover, the amount of by-product amino acids decreased significantly when the gluE and brnE/brnF genes were deleted. It was also demonstrated that there was no effect on the growth of the strain when the gluE or lysP gene was deleted, whereas the biomass of C. glutamicum WL1702 (ΔbrnE/ΔbrnF) in the fermentation medium was significantly reduced in comparison with that of the wild type. These results also provide useful information for enhancing the production of L-lysine or other amino acids by C. glutamicum.
谷氨酸棒杆菌在生物技术生产 L-赖氨酸方面有着悠久而成功的历史。除了代谢途径的调节外，细胞内和细胞外的运输系统对于 L-赖氨酸或其副产物的细胞代谢也至关重要。在这里，研究人员分别通过基因敲除的方法对三种氨基酸跨膜转运蛋白，即 GluE、BrnE/BrnF 和 LysP 进行了研究。与野生型菌株相比，在谷氨酸棒杆菌 23604 中敲除 gluE、brnE/brnF 和 lysP 基因后，L-赖氨酸的产量分别提高了 9.0%、12.3%和 10.0%。此外，当敲除 gluE 和 brnE/brnF 基因时，副产物氨基酸的含量显著减少。当敲除 gluE 或 lysP 基因时，菌株的生长没有影响，而在发酵培养基中，谷氨酸棒杆菌 WL1702（ΔbrnE/ΔbrnF）的生物量与野生型相比显著降低。这些结果也为通过谷氨酸棒杆菌提高 L-赖氨酸或其他氨基酸的产量提供了有用的信息。
