Enhancement Of Angucycline Production By Combined Uv Mutagenesis And Ribosome Engineering And Fermentation Optimization Instreptomyces Dengpaensisxzhg99(T)

Strain improvement ofStreptomyces dengpaensisXZHG99(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 arpsLmutant (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.