Polymyxin is a lipopeptide antibiotic that is effective against multidrug-resistant Gram-negative bacteria. However, its clinical development is limited due to low titer and the presence of homologs. To address this, the polymyxin gene cluster was integrated into , and from was expressed heterologously, enabling recombinant to synthesize polymyxin B. Regulating NRPS domain inhibited formation of polymyxin B2 and B3. The production of polymyxin B increased to 329.7 mg/L by replacing the native promoters of , , and with P, C2up, and P, respectively. Further enhancement in this production, up to 616.1 mg/L, was achieved by improving the synthesis ability of 6-methyloctanoic acid compared to the original strain expressing polymyxin heterologously. Additionally, incorporating an anikasin-derived domain into the hybrid nonribosomal peptide synthase of polymyxin increased the B1 ratio in polymyxin B from 57.5% to 62.2%. Through optimization of peptone supply in the fermentation medium and fermentation in a 5.0-L bioreactor, the final polymyxin B titer reached 962.1 mg/L, with a yield of 19.24 mg/g maltodextrin and a productivity of 10.02 mg/(L·h). This study demonstrates a successful approach for enhancing polymyxin B production and increasing the B1 ratio through combinatorial metabolic engineering.

中文翻译：

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用于从头生产多粘菌素 B 的枯草芽孢杆菌组合代谢工程


多粘菌素是一种脂肽抗生素，可有效对抗多重耐药革兰氏阴性菌。然而，由于滴度低和同系物的存在，其临床开发受到限制。为了解决这个问题，将多粘菌素基因簇整合到 ，并异源表达，使重组体能够合成多粘菌素 B。调节 NRPS 结构域抑制多粘菌素 B2 和 B3 的形成。通过分别用 P、C2up 和 P 替换 、 和 的天然启动子，多粘菌素 B 的产量增加至 329.7 mg/L。与异源表达多粘菌素的原始菌株相比，通过提高 6-甲基辛酸的合成能力，产量进一步提高，高达 616.1 mg/L。此外，将阿尼卡辛衍生结构域掺入多粘菌素的杂合非核糖体肽合酶中，可将多粘菌素 B 中的 B1 比率从 57.5% 增加至 62.2%。通过优化发酵培养基中的蛋白胨供应和5.0L生物反应器中的发酵，最终多粘菌素B效价达到962.1mg/L，麦芽糊精产量为19.24mg/g，生产率为10.02mg/(L·h) 。这项研究展示了一种通过组合代谢工程提高多粘菌素 B 产量和提高 B1 比例的成功方法。