Efficient trans-aconitic acid production using systematically metabolic engineered Escherichia coli

<i>trans</i>-Aconitic acid (TAA) is a versatile platform biochemical exhibiting extensive applications. In this work, <i>Escherichia coli</i> W3110 (DE3) was metabolic modified for the de novo biosynthesis of TAA. Firstly, a pyruvate accumulation chassis strain <i>E. coli</i> W3110-P6 was constructed through deletion of six byproducts generation genes. Secondly, the aconitate isomerase was screened from four candidates and co-overexpressed with TAA transporter to construct heterologous TAA biosynthetic pathway in <i>E. coli</i> W3110-P6. Thirdly, the genes <i>pyc</i> ^P458S encoding a feedback-insensitive pyruvate carboxylase and <i>gltA</i> encoding an allosterically unaffected citrate synthase were overexpressed, and <i>aceA</i> encoding the isocitrate lyase was deleted, to increase precursor supply and TAA generation of the recombinant <i>E. coli</i>. Finally, the fermentation condition of the obtained strain <i>E. coli</i> W3110-TAA08 was optimized. TAA at a concentration of 37.32 g/L was generated within 40 h, with a yield of 0.76 g/g glucose and a productivity of 0.93 g/L/h.