Biosynthesis by microorganisms using renewable feedstocks is an important approach for realizing sustainable chemical manufacturing. However, cell-to-cell variation in biosynthesis capability during fermentation restricts the robustness and efficiency of bioproduction, hampering the industrialization of biosynthesis. Herein, we developed an inducible population quality control system (iPopQC) for dynamically modulating the producing and nonproducing subpopulations of engineered Bacillus subtilis, which was constructed via inducible promoter- and metabolite-responsive biosensor-based genetic circuit for regulating essential genes. Moreover, iPopQC achieved a 1.97-fold increase in N-acetylneuraminic acid (NeuAc) titer by enriching producing cell subpopulation during cultivation, representing 52% higher than that of previous PopQC. Strains with double-output iPopQC cocoupling the expression of double essential genes with NeuAc production improved production robustness further, retaining NeuAc production throughout 96 h of fermentation, upon which the strains cocoupling one essential gene expression with NeuAc production abolished the production ability.

中文翻译：

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用于改进 N-乙酰神经氨酸生物合成的工程枯草芽孢杆菌的可诱导群体质量控制

微生物利用可再生原料进行生物合成是实现可持续化学制造的重要途径。然而，发酵过程中细胞间生物合成能力的差异限制了生物生产的稳健性和效率，阻碍了生物合成的工业化。在此，我们开发了一种可诱导的群体质量控制系统 (iPopQC)，用于动态调节工程枯草芽孢杆菌的生产和非生产亚群，该系统是通过基于可诱导启动子和代谢物响应的生物传感器的遗传电路构建的，用于调节必需基因。此外，iPopQC 的N增加了 1.97 倍-乙酰神经氨酸（NeuAc）滴度通过在培养过程中富集生产细胞亚群，比之前的 PopQC 高 52%。具有双输出 iPopQC 的菌株将双必需基因的表达与 NeuAc 生产偶联进一步提高了生产稳健性，在整个 96 小时的发酵过程中保持 NeuAc 生产，在此之后，将一种必需基因表达与 NeuAc 生产偶联的菌株消除了生产能力。