Highly Efficient Production of Menaquinone‑7 from Glucose by Metabolically Engineered Escherichia coli

• Published in: ACS synthetic biology 2021-04, Vol.10 (4), p.756-765
• Main Authors: Gao, Quanxiu, Chen, Hao, Wang, Gaoyan, Yang, Wei, Zhong, Xiaotong, Liu, Jiezheng, Huo, XiaoJing, Liu, Weifeng, Huang, Jianzhong, Tao, Yong, Lin, Baixue
• Format: Article
• Language: English
• Subjects: Escherichia coli - metabolism; Glucose - metabolism; Naphthols - metabolism; Vitamin K 2 - analogs & derivatives; Vitamin K 2 - metabolism
• ISSN: 2161-5063; 2161-5063
• DOI: 10.1021/acssynbio.0c00568

Menaquinone-7 (MK-7) possesses wide health and medical value, and the market demand for MK-7 has increased. Metabolic engineering for MK-7 production in Escherichia coli still remains challenging due to the characteristics of the competing quinone synthesis, and cells mainly synthesized menaquinones under anaerobic conditions. To increase the production of MK-7 in engineered E. coli strains under aerobic conditions, we divided the whole MK-7 biosynthetic pathway into three modules (MVA pathway, DHNA pathway, and MK-7 pathway) and systematically optimized each of them. First, by screening and enhancing Idi expression, the amounts of MK-7/DMK-7 increased significantly. Then, in the MK-7 pathway, by combinatorial overexpression of endogenous MenA and exogenous UbiE, and fine-tuning the expression of HepPPS, MenA, and UbiE, 70 μM MK-7 was achieved. Third, the DHNA synthetic pathway was enhanced, and 157 μM MK-7 was achieved. By the combinational metabolic engineering strategies and membrane engineering, an efficient metabolic engineered E. coli strain for MK-7 synthesis was developed, and 200 μM (129 mg/L) MK-7 was obtained in shake flask experiment, representing a 306-fold increase compared to the starting strain. In the scale-up fermentation, 2074 μM (1350 mg/L) MK-7 was achieved after 52 h fermentation with a productivity of 26 mg/L/h. This is the highest titer of MK-7 ever reported. This study offers an alternative method for MK-7 production from biorenewable feedstock (glucose) by engineered E. coli. The high titer of our process should make it a promising cost-effective resource for MK-7.