Development of a versatile chassis for the efficient production of diverse type II polyketides

Type II polyketides (T2PKs) exhibit a wide range of structural diversity and potent pharmacological activities. However, the optimal chassis for the synthesis of T2PKs remains elusive, impeding the effective mining and production of these compounds. In this study, we identify Streptomyces aureofaciens J1-022, a high-yield producer of chlortetracycline, as a promising chassis for T2PKs synthesis. To mitigate precursor competition, we execute an in-frame deletion of two endogenous T2PKs gene clusters, resulting in a pigmented-faded host, designated Chassis2.0. Compared to conventional Streptomyces chassis, Chassis2.0 demonstrates enhanced efficiency in the production of oxytetracycline, achieving a 370% increase relative to commercial production strains. Additionally, the tri-ring type T2PKs, which includes actinorhodin and flavokermesic acid, are synthesized in Chassis2.0 with high efficiency. Furthermore, an unidentified biosynthetic gene cluster (BGC) associated with pentangular T2PKs is directly activated, leading to the production of a structurally distinct TLN-1. In conclusion, we successfully achieve the efficient synthesis of tri-ring type pigmented products, the overproduction of tetra-ring antibiotics, and the discovery of penta-ring type polyketides in Chassis2.0. These findings underscore the potential of Chassis2.0 as an optimal platform for the discovery and overproduction of T2PKs.