Enhanced ascomycin production in Streptomyces hygroscopicus var. ascomyceticus by employing polyhydroxybutyrate as an intracellular carbon reservoir and optimizing carbon addition

Abstract Background Ascomycin is a multifunctional antibiotic produced by Streptomyces hygroscopicus var. ascomyceticus . As secondary metabolite, the production of ascomycin often limited shortage precursors during late fermentation phase. Polyhydroxybutyrate an intracellular polymer accumulated prokaryotic microorganisms. Developing polyhydroxybutyrate as carbon reservoir for precursor synthesis great significance to improve yield ascomycin. Results The characteristics parent strain S. FS35 showed that accumulation and decomposition was respectively correlated with cell growth production. co-overexpression exogenous gene phaC native fkbU increased both biomass yield. Comparative transcriptional analysis storage exponential phase accelerated biosynthesis processes stimulating utilization sources, while stationary enhancing metabolic flux through primary pathways. comparative cofactor concentrations confirmed depended on supply NADH. At low sugar found in phase, optimization source addition further strengthened metabolism increasing total concentration cofactors. Finally, medium 22 g/L starch 52 dextrin, 626.30 mg/L, which 2.11-fold higher than initial (296.29 mg/L). Conclusions Here we report first time beneficial acting reservoir, stored polymers when sources are abundant depolymerized into monomers insufficient. successful application output provides new strategy improving yields other metabolites.