Metabolic Engineering of the MEP Pathway in Bacillus subtilis for Increased Biosynthesis of Menaquinone-7

ACS Synth Biol. 2019 Jul 19;8(7):1620-1630. doi: 10.1021/acssynbio.9b00077. Epub 2019 Jun 28.

Abstract

Vitamin K is essential for blood coagulation and plays important roles in bone and cardiovascular health. Menaquinone-7 (MK-7) is one form of vitamin K that is especially useful due to its long half-life in the circulation. MK-7 is difficult to make via organic synthesis, and is thus commonly produced by fermentation. This study aimed to genetically modify Bacillus subtilis cultures to increase their MK-7 yield and reduce production costs. We constructed 12 different strains of B. subtilis 168 by overexpressing different combinations of the rate-limiting enzymes Dxs, Dxr, Idi, and MenA. We observed an 11-fold enhancement of production in the best-performing strain, resulting in 50 mg/L MK-7. Metabolite analysis revealed new bottlenecks in the pathway at IspG and IspH, which suggest avenues for further optimization. This work highlights the usefulness of Bacillus subtilis for industrial production of high value compounds.

Keywords: MEP pathway; biofilm formation; menaquinone-7; metabolic engineering; vitamin K.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / metabolism*
  • Culture Media / metabolism
  • Fermentation / physiology
  • Metabolic Engineering / methods
  • Receptor, EphB6 / metabolism*
  • Signal Transduction / physiology*
  • Vitamin K 2 / analogs & derivatives*
  • Vitamin K 2 / metabolism

Substances

  • Bacterial Proteins
  • Culture Media
  • Receptor, EphB6
  • Vitamin K 2
  • vitamin MK 7