Enhanced production of glutarate by using anaerobic-aerobic shift cultivation and an anaerobically inducible promoter in an engineered Escherichia coli

5 years ago

Enhanced production of glutarate by using anaerobic-aerobic shift cultivation and an anaerobically inducible promoter in an engineered Escherichia coli

Recently we constructed a recombinant Escherichia coli for glutarate production using α-ketoacids reduction pathway, in which the central carbon metabolite α-ketoglutarate is reduced to 2-hydroxyglutarate then converted to glutarate. However, the production titer of glutarate was low, which may be due to the oxygen-sensitive nature of 2-hydroxyglutaryl-CoA dehydratase (HgdABC) while the anaerobic cell metabolism is not so active. To achieve higher production of glutarate, an aerobic-anaerobic shift strategy was developed by fast growing cells aerobically, followed by a shift to anaerobic cultivation to ensure the activity of HgdABC for glutarate biosynthesis. The two-stage cultivation strategy resulted in approximately 30% higher production titer than the original anaerobic cultivation. Furthermore, an anaerobically-inducible nar promoter was employed to control the hgdABC expression, and the newly engineered strain showed efficient expression of hgdABC responding to aerobic-anaerobic shift during two-stage cultivation. Finally, the glutarate production titer was doubled, reaching 11.6mg/L. The work demonstarted the potential of the integration of bioprocess engineering and metabolic engineering for enhancing bulk chemicals production by an engineered microorganism.

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DOI: S1359511317309625