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

trans-Aconitic acid (TAA) is a versatile platform biochemical exhibiting extensive applications. In this work, Escherichia coli W3110 (DE3) was metabolic modified for the de novo biosynthesis of TAA. Firstly, a pyruvate accumulation chassis strain E. coli 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 E. coli W3110-P6. Thirdly, the genes pyc P458S encoding a feedback-insensitive pyruvate carboxylase and gltA encoding an allosterically unaffected citrate synthase were overexpressed, and aceA encoding the isocitrate lyase was deleted, to increase precursor supply and TAA generation of the recombinant E. coli. Finally, the fermentation condition of the obtained strain E. coli 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.