Increased production of yersiniabactin and an anthranilate analog through media optimization

Yersiniabactin (Ybt) is a mixed nonribosomal peptide-polyketide natural product that binds a wide range of metals with the potential to impact processes requiring metal retrieval and removal. In this work, we substantially improved upon the heterologous production of Ybt and an associated anthranilate analog through systematic screening and optimization of culture medium components. Specifically, a Plackett-Burman design-of-experiments methodology was used to screen 22 components and to determine those contributing most to siderophore production. L-cysteine, L-serine, glucose, and casamino acids significantly contributed to the production of both compounds. Using this approach together with metabolic engineering of the base biosynthetic process, Ybt and the anthranilate analog titers were increased to 867 ± 121 mg/L and 16.6 ± 0.3 mg/L, respectively, an increase of ∼38 and ∼79-fold relative to production in M9 medium.