Production of Itaconic Acid By Enhancing Functional Expression of Cada in Escherichia coli

To date, although the microbial fermentation process has been considered as the sustainable technology to produce valuable chemicals, it is economically unfavorable than the petrochemical process in the production costs and yields. Accordingly, the increase of the productivity achieved by the biological process is to be the first priority problem. Itaconic acid (IA) is an unsaturated dicarboxylic acid which utilized as biochemical building block for production of resins, plastics, paints and synthetic fiber. IA is considered as future bio-based platform chemical. However, IA hasn’t been improved during the past 40 years owing to physiological and genetical disadvantages of Aspergillus terreus. In these contexts, we previously verified that both the functional expression of cis aconitate decarboxylase (CadA), which converts the citric acid cycle intermediate cis-aconitate to IA, and nitrogen limitation were important factors in IA production using Escherichia coli. The latter by which contents of direct and indirect precursors in the cytosol was increased could be further optimized through metabolic engineering. To this goal, genes such as citrate synthase (gltA) and phosphate acetyltransferase (pta) were overexpressed and/or deleted. We observed that the overexpression of genes to additionally supply precursors was more effective on the productivity of IA than deletion.