Remarkable enhancement of bleomycin production through precise amplification of its biosynthetic gene cluster in Streptomyces verticillus

Amplification of biosynthetic gene clusters is important to increase secondary metabolite production. However, the copy number of amplified gene clusters is difficult to control precisely. In this study, the tandem amplification of a 70 kb bleomycin biosynthetic gene cluster was precisely regulated through the combined strategy of a ZouA-dependent DNA amplification system and double-reporter-guided recombinant selection in Streptomyces verticillus ATCC15003. The production of bleomycin in the recombinant strain containing six copies of the bleomycin gene cluster was 9.59-fold higher than that in the wild-type strain. The combined strategy used in this study is powerful and applicable for precisely regulating the amplification of gene clusters and improving the corresponding secondary metabolite production.