Phosphoenolpyruvate-supply module in Escherichia coli improves N-acetyl-D-neuraminic acid biocatalysis.

Objectives: N-Acetyl-D-neuraminic acid (Neu5Ac) is often synthesized from exogenous N-acetylglucosamine (GlcNAc) and excess pyruvate. We have previously constructed a recombinant Escherichia coli strain for Neu5Ac production using GlcNAc and intracellular phosphoenolpyruvate (PEP) as substrates (Zhu et al. Biotechnol Lett 38:1-9, 2016).
Results: PEP synthesis-related genes, pck and ppsA, were overexpressed within different modes to construct PEP-supply modules, and their effects on Neu5Ac production were investigated. All the PEP-supply modules enhanced Neu5Ac production. For the best module, pCDF-pck-ppsA increased Neu5Ac production to 8.6 ± 0.15 g l ^-1 , compared with 3.6 ± 0.15 g l ^-1 of the original strain. Neu5Ac production was further increased to 15 ± 0.33 g l ^-1 in a 1 l fermenter.
Conclusions: The PEP-supply module can improve the intracellular PEP supply and enhance Neu5Ac production, which benefited industrial Neu5Ac production.