The semi-synthetic antibiotic dalbavancin is clinically used in the treatment of severe infections caused by multidrug resistant Gram-positive pathogens. So far, fermentation has still been the only approach for the production of A40926 in the industrial scale, which is used as the precursor of dalbavancin and biosynthesized by the rare actinomycete Nonomuraea gerenzanensis (N. gerenzanensis). Therefore, it is particularly essential and necessary to enhance the yield of A40926 continually. In this paper, we firstly assessed the activity of 6 heterologous promoters using the enhanced green fluorescence protein (EGFP) reporter system in N. gerenzanensis. Furthermore, the strongest constitutive promoter gapdh confirmed in this study was applied to separately overexpress the total of ten dbv genes involved in the A40926 biosynthesis. PCR and RT-qPCR were successively carried out to verify the mutant and the overexpression of dbv genes. As a consequence, the overexpression of dbv3 and dbv20 genes both increased the A40926 production remarkably. Based on the above consequences, a mutant strain named N320 laboring the co-expression of dbv3 and dbv20 was constructed. The results of fermentation showed that the N320 strain enhanced the yield of A40926 from 163 mg/L to 272 mg/L.

半合成抗生素达巴万星在临床上用于治疗由多重耐药革兰氏阳性菌引起的严重感染。迄今为止，发酵仍是工业规模生产 A40926 的唯一途径，其用作达巴万星的前体，由稀有放线菌Nonomuraea gerenzanensis ( N. gerenzanensis )生物合成。因此，不断提高A40926的收率显得尤为必要和必要。在本文中，我们首先使用增强型绿色荧光蛋白 (EGFP) 报告系统在N.gerenzanensis 中评估了 6 个异源启动子的活性。此外，最强的组成型启动子gapdh在这项研究中证实的 被应用于分别过表达参与 A40926 生物合成的总共十个dbv基因。先后进行PCR和RT-qPCR验证dbv基因的突变和过表达。因此，dbv3和dbv20基因的过表达均显着增加了 A40926 的产量。基于上述结果，构建了一个名为 N320 的突变菌株，它使dbv3和dbv20共表达。发酵结果表明，N320菌株将A40926的产量从163 mg/L提高到272 mg/L。