Menaquinone-7 production in engineered Escherichia coli

Area of Science:

• Biotechnology
• Metabolic Engineering
• Microbial Production

Background:

• Menaquinone-7 (MK-7) is a vital form of vitamin K2 essential for human health.
• Current production methods for MK-7 face limitations, necessitating alternative strategies.
• Escherichia coli offers a promising platform for microbial production of valuable compounds.

Purpose of the Study:

• To engineer Escherichia coli for the efficient production of Menaquinone-7 (MK-7).
• To optimize metabolic pathways for enhanced MK-7 biosynthesis.
• To establish a scalable fermentation process for MK-7.

Main Methods:

• Introduction of heterologous heptaprenyl pyrophosphate synthetase (HepPPS) from Bacillus subtilis.
• Optimization of the mevalonic acid (MVA) pathway and BsHepPPS expression.
• Genetic modification, including deletion of competitive pathway genes (ubiCA, ispB).
• Scale-up fermentation in a 5-L bioreactor under aerobic conditions.

Main Results:

• Achieved the first reported MK-7 production in engineered E. coli.
• Increased MK-7 titer to 2.3 μM through pathway optimization, a 22-fold improvement.
• Reached a final yield of 13.6 μM (8.8 mg/L) MK-7 in scale-up fermentation.
• Identified ubiE as a potential bottleneck in the MK-7 biosynthesis pathway.

Conclusions:

• Metabolic engineering of E. coli is a viable strategy for MK-7 production.
• Optimized pathways and fermentation conditions significantly enhance MK-7 yield.
• Further metabolic engineering targeting ubiE can improve MK-7 production efficiency.