Abstract

Strain improvement of Streptomyces dengpaensis XZHG99^T was performed by combined UV mutagenesis and ribosome engineering, as well as fermentation optimization for enhanced angucycline production (rabelomycin and saquayamycin B1). First, four streptomycin-resistant mutants were obtained after screening of UV mutagenesis and ribosome engineering. Then a rpsL mutant (HTT7) with higher productivity of rabelomycin and saquayamycin B1 was selected according to genetic screening and HPLC/LC-MS analyses, whose maximum titers of rabelomycin and saquayamycin B1 were 3.6 ± 0.02 mg/L and 7.5 ± 0.04 mg/L, respectively, about fourfold higher than those produced by XZHG99^T. Next, fermentation optimization of HTT7 was successively carried out by single-factor experiments in shake flasks. The titers of rabelomycin and saquayamycin B1 were increased to 11.2 ± 0.04 mg/L and 20.5 ± 0.02 mg/L after optimization of shake flask fermentation conditions, respectively, which was increased about sixfold compared with those produced by XZHG99^T. Finally, the titers of rabelomycin and saquayamycin B1 reached 15.7 ± 0.05 mg/L and 39.9 ± 0.05 mg/L after the scaled-up fermentation, which was 7.8-fold and 11.4-fold higher than those produced by XZHG99^T, respectively. These data demonstrate that the combined empirical strain-breeding approaches are still an effective and convenient pathway to improve strain production ability.

抽象的

的菌株改进链霉菌dengpaensis XZHG99 ^Ť通过组合UV诱变和核糖体工程，以及用于增强angucycline生产（rabelomycin和saquayamycin B1）发酵优化执行。首先，在筛选了紫外线诱变和核糖体工程之后，获得了四个对链霉素具有抗性的突变体。然后通过遗传筛选和HPLC / LC-MS分析，选择了雷贝霉素和萨瓜霉素B1具有较高生产率的rpsL突变体（HTT7），雷贝霉素和萨瓜霉素B1的最大效价分别为3.6±0.02 mg / L和7.5±0.04 mg / L L分别比XZHG99 ^T产生的L高约四倍。接下来，在摇瓶中通过单因素实验连续进行HTT7的发酵优化。rabelomycin和saquayamycin B1的滴度增加到11.2±0.04 mg / L和的摇瓶发酵条件，分别，这增加了大约与那些由XZHG99产生六倍相比优化后20.5±0.02毫克/升^Ť。最后，rabelomycin和saquayamycin B1的滴度达到按比例放大的发酵，这是后15.7±0.05 mg / L和39.9±0.05毫克/升7.8倍和11.4倍比由XZHG99产生更高^Ť分别。这些数据表明，组合的经验应变育种方法仍然是提高应变产生能力的有效且方便的途径。