Phenazines are aromatic compounds with diverse applications in the agricultural, pharmaceutical, and electrochemical industries. Highly substituted natural phenazines are generally synthesized from phenazine-1,6-dicarboxylic acid (PDC) in Streptomyces strains, and different from phenazine-1-carboxylic acid (PCA) derivatives with relatively simple structures produced in Pseudomonas strains. This study achieved selective high production of PDC and provided a modular strategy for the biosynthesis of its derivatives. We first identified a PDC biosynthetic gene cluster (BGC) from Streptomyces lomondensis S015. Bioinformatics analysis, gene deletion, and enzymatic reaction characterized a hypothetical protein (designated as PhzF′) involved in the selective biosynthesis of PDC. Additionally, several metabolic engineering strategies were adopted to reinforce PDC production in Streptomyces coelicolor M1152. PDC production achieved 259.6 mg/L, and PCA was barely detectable in a mineral medium with xylan as the sole carbon source. Likewise, the highest PDC production of 1165.8 mg/L was obtained so far in R5 medium, and the ratio of PDC to total phenazines production achieved 99.3%. Lastly, we expand the PDC production chassis to a modular platform for the production and identification of PDC derivative. This study demonstrated the essential role of PhzF′ in modulating PDC/PCA ratio and the potential of Streptomyces as a platform for the efficient production of PDC and highly substituted phenazine derivatives.

中文翻译：

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天蓝色链霉菌中吩嗪-1,6-二甲酸的增强生物合成

吩嗪是芳香族化合物，在农业、制药和电化学工业中具有多种应用。高取代天然吩嗪一般由链霉菌菌株中的吩嗪-1,6-二甲酸（PDC）合成，与假单胞菌菌株中产生的结构相对简单的吩嗪-1-甲酸（PCA）衍生物不同。本研究实现了PDC的选择性高产量，并为其衍生物的生物合成提供了模块化策略。我们首先从罗蒙链霉菌S015中鉴定出 PDC 生物合成基因簇 (BGC) 。生物信息学分析、基因缺失和酶反应表征了参与 PDC 选择性生物合成的假设蛋白（称为 PhzF'）。此外，还采用了多种代谢工程策略来增强天蓝色链霉菌M1152 中 PDC 的产生。PDC 产量达到 259.6 mg/L，在以木聚糖为唯一碳源的矿物介质中几乎检测不到 PCA。同样，迄今为止，R5培养基中PDC产量最高为1165.8 mg/L，PDC占吩嗪总产量的比例达到99.3%。最后，我们将PDC生产底盘扩展为模块化平台，用于PDC衍生品的生产和识别。这项研究证明了 PhzF' 在调节 PDC/PCA 比例中的重要作用，以及链霉菌作为高效生产 PDC 和高度取代吩嗪衍生物平台的潜力。