Multiplexed site-specific genome engineering for overproducing bioactive secondary metabolites in actinomycetes

•A general approach for the stable amplification of secondary metabolite biosynthetic gene clusters in actinomycetes.•A panel of powerful Streptomyces coelicolor heterologous hosts for genome mining of natural products.•A novel DNA editing method for rapidly refactoring gene clusters, including deletion and replacement.

Actinomycetes produce a large variety of pharmaceutically active compounds, yet production titers often require to be improved for discovery, development and large-scale manufacturing. Here, we describe a new technique, multiplexed site-specific genome engineering (MSGE) via the 'one integrase-multiple attB sites' concept, for the stable integration of secondary metabolite biosynthetic gene clusters (BGCs). Using MSGE, we achieved five-copy chromosomal integration of the pristinamycin II (PII) BGC in Streptomyces pristinaespiralis, resulting in the highest reported PII titers in flask and batch fermentations (2.2 and 2 g/L, respectively). Furthermore, MSGE was successfully extended to develop a panel of powerful Streptomyces coelicolor heterologous hosts, in which up to four copies of the BGCs for chloramphenicol or anti-tumour compound YM-216391 were efficiently integrated in a single step, leading to significantly elevated productivity (2-23 times). Our multiplexed approach holds great potential for robust genome engineering of industrial actinomycetes and novel drug discovery by genome mining.