Metabolic engineering of Corynebacterium glutamicum for the production of itaconate

The capability of Corynebacterium glutamicum for glucose-based synthesis of itaconate was explored, which can serve as building block for production of polymers, chemicals, and fuels. C glutamicum was highly tolerant to itaconate and did not metabolize it. Expression of the Aspergillus terreus CAD1 gene encoding cis-aconitate decarboxylase (CAD) in strain ATCC13032 led to the production of 1.4 mM itaconate in the stationary growth phase. Fusion of CAD with the Escherichia colt maltose-binding protein increased its activity and the itaconate titer more than two-fold. Nitrogen-limited growth conditions boosted CAD activity and itaconate titer about 10-fold to values of 1440 mU mg(-1) and 30 mM. Reduction of isocitrate dehydrogenase activity via exchange of the ATG start codon to GTG or TUG resulted in maximal itaconate titers of 60 mM (7.8 gl(-1)), a molar yield of 0.4 mol mol(-1), and a volumetric productivity of 2.1 mmol 1(-1) h(-1). (C) 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.