Xu Xuechen, Wang Haomiao, Chen Xiulai, Wu Jing, Gao Cong, Song Wei, Wei Wanqing, Liu Jia, Liu Yadi, Liu Liming
Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China.
School of Life Sciences and Health Engineering, Jiangnan University, Wuxi 214122, Jiangsu, China.
Sheng Wu Gong Cheng Xue Bao. 2024 Aug 25;40(8):2513-2527. doi: 10.13345/j.cjb.240049.
L-lysine is an essential amino acid with broad applications in the animal feed, human food, and pharmaceutical industries. The fermentation production of L-lysine by has limitations such as poor substrate utilization efficiency and low saccharide conversion rates. We deleted the global regulatory factor gene and introduced heterologous genes, including the maltose phosphotransferase genes () from , to enhance the use efficiency of disaccharides and trisaccharides. The engineered strain . XC3 demonstrated improved L-lysine production, yield, and productivity, which reached 160.00 g/L, 63.78%, and 4.44 g/(L‧h), respectively. Furthermore, we overexpressed the glutamate dehydrogenase gene () and assimilated nitrate reductase genes () from . , along with nitrite reductase genes () from . , in strain . XC3. This allowed the construction of . XC4 with a nitrate assimilation pathway. The L-lysine production, yield, and productivity of . XC4 were elevated to 188.00 g/L, 69.44%, and 5.22 g/(L‧h), respectively. After optimization of the residual sugar concentration and carbon to nitrogen ratio, the L-lysine production, yield, and productivity were increased to 204.00 g/L, 72.32%, and 5.67 g/(L‧h), respectively, in a 5 L fermenter. These values represented the increases of 40.69%, 20.03%, and 40.69%, respectively, compared with those of the starting strain XC1. By engineering the substrate utilization pathway, we successfully constructed a high-yield L-lysine producing strain, laying a solid foundation for the industrial production of L-lysine.
L-赖氨酸是一种必需氨基酸，在动物饲料、人类食品和制药行业有着广泛应用。通过发酵生产L-赖氨酸存在底物利用效率低和糖类转化率低等局限性。我们删除了全局调控因子基因，并引入了包括来自[具体来源]的麦芽糖磷酸转移酶基因（[基因名称]）在内的异源基因，以提高二糖和三糖的利用效率。工程菌株XC3的L-赖氨酸产量、产率和生产率均有所提高，分别达到160.00 g/L、63.78%和4.44 g/(L‧h)。此外，我们在菌株XC3中过表达了来自[具体来源]的谷氨酸脱氢酶基因（[基因名称]）和同化硝酸还原酶基因（[基因名称]），以及来自[具体来源]的亚硝酸还原酶基因（[基因名称]）。这使得能够构建具有硝酸盐同化途径的XC4。XC4的L-赖氨酸产量、产率和生产率分别提高到188.00 g/L、69.44%和5.22 g/(L‧h)。在优化残糖浓度和碳氮比后，在5 L发酵罐中L-赖氨酸产量、产率和生产率分别提高到204.00 g/L、72.32%和5.67 g/(L‧h)。与起始菌株XC1相比，这些值分别提高了40.69%、20.03%和40.69%。通过改造底物利用途径，我们成功构建了一株高产L-赖氨酸生产菌株，为L-赖氨酸的工业化生产奠定了坚实基础。
