Metabolic engineering aims to achieve high yields of desired products. The most common strategies focus on optimization of metabolic flux distributions. The dynamic activation or inhibition of gene expression through quorum sensing (QS) has been applied to metabolic engineering. In this study, we designed and constructed a series of QS-based bifunctional dynamic switches (QS switches) capable of synchronizing the up-regulation and down-regulation of genes at different times and intervals. The bifunctional QS switches were based on the Esa QS system, because EsaR regulatory proteins can act as transcriptional activator and repressor. The QS switches' effectiveness and feasibility were verified through fluorescence characterization. Finally, the QS switches were applied to the production of 5-aminolevulinic acid (ALA) and poly-β-hydroxybutyrate (PHB) to solve two key metabolic engineering problems: necessary gene knockout and redirection of metabolic flux. The production of PHB and ALA was increased 6- and 12-fold in Escherichia coli, respectively.

中文翻译：

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基于群体感应的双功能开关及其在解决两个关键代谢工程问题中的应用。

代谢工程旨在实现所需产品的高收率。最常见的策略集中在优化代谢通量分布上。通过群体感应（QS）的基因表达的动态激活或抑制已应用于代谢工程。在这项研究中，我们设计并构建了一系列基于QS的双功能动态开关（QS开关），它们能够在不同的时间和间隔同步基因的上调和下调。双功能QS开关基于Esa QS系统，因为EsaR调节蛋白可以充当转录激活因子和阻遏因子。通过荧光表征验证了QS开关的有效性和可行性。最后，QS开关用于生产5-氨基乙酰丙酸（ALA）和聚-β-羟基丁酸酯（PHB），以解决两个关键的代谢工程问题：必要的基因敲除和代谢通量的重定向。在大肠杆菌中，PHB和ALA的产量分别增加了6倍和12倍。