Fumarate is a multifunctional dicarboxylic acid in the tricarboxylic acid cycle, but microbial engineering for fumarate production is limited by the transmission efficiency of its biosynthetic pathway. Here, pathway engineering was used to construct the noncyclic glyoxylate pathway for fumarate production. To improve the transmission efficiency of intermediate metabolites, pathway optimization was conducted by fluctuating gene expression levels to identify potential bottlenecks and then remove them, resulting in a large increase in fumarate production from 8.7 to 16.2 g/L. To further enhance its transmission efficiency of targeted metabolites, transporter engineering was used by screening the C4-dicarboxylate transporters and then strengthening the capacity of fumarate export, leading to fumarate production up to 18.9 g/L. Finally, the engineered strain E. coli W3110△4-P(H)CAI(H)SC produced 22.4 g/L fumarate in a 5-L fed-batch bioreactor. In this study, we offered rational metabolic engineering and flux optimization strategies for efficient production of fumarate. These strategies have great potential in developing efficient microbial cell factories for production of high-value added chemicals.

中文翻译：

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工程设计非环状乙醛酸途径在大肠杆菌中生产富马酸盐的传输效率。

富马酸是三羧酸循环中的多功能二羧酸，但用于富马酸生产的微生物工程受到其生物合成途径的传递效率的限制。在这里，途径工程被用来构建富马酸生产的非环状乙醛酸途径。为了提高中间代谢物的传递效率，通过波动基因表达水平进行途径优化，以识别潜在的瓶颈，然后消除它们，导致富马酸盐产量从 8.7 到 16.2 g/L 大幅增加。为了进一步提高其对目标代谢物的传输效率，通过筛选C4-二羧酸转运蛋白，然后加强富马酸输出能力，使富马酸产量达到18.9 g/L。最后，工程菌株大肠杆菌 W3110△4-P(H)CAI(H)SC 在 5-L 分批补料生物反应器中产生 22.4 g/L 富马酸盐。在这项研究中，我们为有效生产富马酸盐提供了合理的代谢工程和通量优化策略。这些策略在开发生产高附加值化学品的高效微生物细胞工厂方面具有巨大潜力。