Enhanced itaconic acid production by self-assembly of two biosynthetic enzymes in Escherichia coli.

Here, we described a novel strategy for the production of itaconic acid in Escherichia coli by self-assembly of aconitase (ACO) and cis-aconitate decarboxylase (CAD) existing in the metabolic pathway of itaconic acid via the protein-peptide interactions of PDZ domain and PDZ ligand. Co-expression of ACO and CAD in E. coli (uCA) resulted in low levels of itaconate (117.25 mg/L) after 48 h fermentation while the itaconate titre was significantly improved up to 222.15 mg/L by self-assembly of ACO-PDZ (APd) and CAD-PDZlig (CPl) in E. coli (sPP) under the same conditions. To further confirm the effect of self-assembly, the itaconate catalyzed from sodium citrate was determined. The sPP was extra efficacious in the early catalytic period, showing approximately threefold itaconate yields increased after 2 h catalysis, when compared to uCA. Furthermore, the itaconate production of sPP was increased from 5 to 8.7 g/L after 30 h of reaction compared to uCA. This self-assembly strategy showed remarkable potential for the further improvement of itaconate production. Biotechnol. Bioeng. 2017;114: 457-462. © 2016 Wiley Periodicals, Inc.