Iteratively improving natamycin production in Streptomyces gilvosporeus by a large operon-reporter based strategy

• Published in: Metabolic engineering 2016-11, Vol.38, p.418-426
• Main Authors: Wang, Yemin, Tao, Zhengsheng, Zheng, Hualiang, Zhang, Fei, Long, Qingshan, Deng, Zixin, Tao, Meifeng
• Format: Article
• Language: English
• Subjects: Biosynthetic Pathways - genetics; Gene Expression Profiling - methods; Genes, Reporter - genetics; Genetic Enhancement - methods; Large genes; Metabolic Engineering - methods; Metabolic Flux Analysis - methods; Metabolic Networks and Pathways - genetics; Multigene Family - genetics; Natamycin; Natamycin - biosynthesis; Natamycin - isolation & purification; Non-ribosomal peptide synthetase; Operon - genetics; Polyketide synthase; Polyketide Synthases - genetics; Reporter; Species Specificity; Strain improvement; Streptomyces - classification; Streptomyces - physiology
• ISSN: 1096-7176; 1096-7184
• DOI: 10.1016/j.ymben.2016.10.005

Many high-value secondary metabolites are assembled by very large multifunctional polyketide synthases or non-ribosomal peptide synthetases encoded by giant genes, for instance, natamycin production in an industrial strain of Streptomyces gilvosporeus. In this study, a large operon reporter-based selection system has been developed using the selectable marker gene neo to report the expression both of the large polyketide synthase genes and of the entire gene cluster, thereby facilitating the selection of natamycin-overproducing mutants by iterative random mutagenesis breeding. In three successive rounds of mutagenesis and selection, the natamycin titer was increased by 110%, 230%, and 340%, respectively, and the expression of the whole biosynthetic gene cluster was correspondingly increased. An additional copy of the natamycin gene cluster was found in one overproducer. These findings support the large operon reporter-based selection system as a useful tool for the improvement of industrial strains utilized in the production of polyketides and non-ribosomal peptides. •Improving industrial strains of Streptomyces through a novel selection system.•Selection system utilizes neo reporter gene fused to natamycin biosynthetic operon.•Mutagenesis increased natamycin production of an industrial strain by 3.4-fold.•Expression of entire gene cluster increased in natamycin-overproducing mutants.