Efficient production of ectoine from Jerusalem artichoke using engineered Escherichia coli

In this study, a recombinant Escherichia coli strain was constructed to produce ectoine from Jerusalem artichoke through modular pathway engineering. First, a promoter-optimized ectoine synthesis module was integrated into the chromosome using multiple copies. Then, the introduction and expression of inulin hydrolase was optimized because inulin cannot be directly utilized. Subsequently, Fructose transport and phosphorylation, glycolysis, and oxaloacetate supply module were enhanced separately and in combination to improve ectoine production and substrate utilization. The strain ETC16 (co-expression of gapA, ppc, and fruK, ΔiclR) produced 6.51 g/L ectoine with 0.13 g/g inulin. Furthermore, the raw inulin extract and monosodium glutamate (MSG) residue were optimized for ectoine production. Finally, 35.60 g/L of ectoine with a yield of 0.36 g/g inulin was achieved in a 7.5 L fermenter. This study revealed a potential method of non-food fermentation to produce high-value products.