Metabolic engineering of Bacillus subtilis for high‐titer production of menaquinone‐7

Abstract

AbstractMenaquinone‐7 (MK‐7) is a member of vitamin K2 used for prevention from osteoporosis and cardiovascular calcification. This study constructed Bacillus subtilis strains for high‐titer production of MK‐7 through metabolic engineering approaches. In B. subtilis, MK‐7 biosynthesis was categorized into five modules: glycerol dissociation pathway, shikimate pathway, pyrimidine metabolic pathway, methylerythritol phosphate pathway, and MK‐7 pathway. Overexpression of GlpK and GlpD (glycerol dissociation pathway) led to a ~10% increase in the MK‐7 titer. Deletion of the genes mgsA and araM increased the MK‐7 production by 15%. Furthermore, overexpression of AroGD146N (shikimate pathway), PyrGE156K (pyrimidine metabolic pathway), HepS (methylerythritol phosphate pathway), and VHb could also increase the MK‐7 titer. Finally, we obtained a recombinant strain BSMK_11 with simultaneous overexpressing the genes glpK, glpD, aroG fbr, pyrG fbr, hepS, vgb, and knockouting the genes mgsA and araM, and the MK‐7 titer reached 281.4 ± 5.0 mg/L (i.e., 12.0 mg/g DCW) in a 5 L fermenter.