Strategic engineering for overproduction of oviedomycin, a Type II polyketide, in Escherichia coli

This study aimed to develop a metabolically engineered Escherichia coli strain capable of producing oviedomycin, a type II angucyclinone polyketide compound with anticancer activity. We first addressed the challenges of in vivo reassembly of the type II polyketide synthase machinery in E. coli. These included co-expressing molecular chaperones, rare tRNAs, and a fusion tag to enhance the solubility of all proteins from the oviedomycin biosynthetic gene cluster in Streptomyces antibioticus. After the soluble expression of all the proteins was confirmed, oviedomycin production was improved by reducing the accumulation of the intermediate 3-dehydrorabelomycin through substrate channeling using the CipB scaffold protein from Photorhabdus luminescens. In addition, the AcrAB-TolC efflux transporter system was introduced to enhance the growth of the producing strain, leading to higher oviedomycin yields. Ultimately, fed-batch fermentation with the final strain produced 120 mg/L oviedomycin from glucose within 24 h. These strategies have marked significant progress in the construction of biosynthetic pathways for the heterologous production of type II polyketides in E. coli, offering promising potential for producing various natural products with industrial applications.