Production of itaconate by whole-cell bioconversion of citrate mediated by expression of multiple cis-aconitate decarboxylase (cadA) genes in Escherichia coli

Abstract

Itaconate, a C5 unsaturated dicarboxylic acid, is an important chemical building block that is used in manufacturing high-value products, such as latex and superabsorbent polymers. Itaconate is produced by fermentation of sugars by the filamentous fungus Aspergillus terreus. However, fermentation by A. terreus involves a long fermentation period and the formation of various byproducts, resulting in high production costs. E. coli has been developed as an alternative for producing itaconate. However, fermentation of glucose gives low conversion yields and low productivity. Here, we report the whole-cell bioconversion of citrate to itaconate with enhanced aconitase and cis-aconitate decarboxylase activities by controlling the expression of multiple cadA genes. In addition, this bioconversion system does not require the use of buffers, which reduces the production cost and the byproducts released during purification. Using this whole-cell bioconversion system, we were able to catalyze the conversion of 319.8 mM of itaconate (41.6 g/L) from 500 mM citrate without any buffer system or additional cofactors, with 64.0% conversion in 19 h and a productivity of 2.19 g/L/h. Our bioconversion system suggests very high productivity for itaconate production.

Mitochondrial metabolism regulates macrophage biology

“…Oxaloacetate is needed for NO and ROS production by providing NADPH (30). In addition, citrate is acted on by the mitochondrial aconitase 2 (ACO2) to produce cis-aconitate which is further decarboxylated for itaconate synthesis (31). Itaconate acts as a negative regulator of inflammation by inhibiting SDH and the production of the inflammatory cytokines (32).…”

Biomass-Derived Production of Itaconic Acid as a Building Block in Specialty Polymers

“…This strain produced 32 g/L itaconate and a maximum yield of 0.77 mol/(mol glucose). The whole cell bioconversion of citrate proposed by Kim et al [96] can diminish the time and cost of itaconate production. Cys-aconitate decarboxylase ( cadA ) gene from A. terreus and acn from C. glutamicum with an improved expression at optimal conditions (pH 5.5 and 35 °C) produced 41.6 g/L itaconate.…”

Enhanced production of glutaric acid by NADH oxidase and GabD‐reinforced bioconversion from l‐lysine

“…Previous reports had shown that whole‐cell conversion rate could be increased by elevating the expression of the active enzyme, either by increasing the innate enzyme expression or simply by adding more biocatalyst (Kim et al, ; Li et al, ). Therefore, cell concentrations between OD 600 = 10–100 were investigated for optimal conversion without the addition of external NAD + (Figure c).…”