title: Metabolic engineering of itaconate production in Escherichia coli.
abstract: Interest in sustainable development has led to efforts to replace petrochemical-based monomers with biomass-based ones. Itaconic acid, a C5-dicarboxylic acid, is a potential monomer for the chemical industry with many prospective applications. cis-aconitate decarboxylase (CadA) is the key enzyme of itaconate production, converting the citric acid cycle intermediate cis-aconitate into itaconate. Heterologous expression of cadA from Aspergillus terreus in Escherichia coli resulted in low CadA activities and production of trace amounts of itaconate on Luria-Bertani (LB) medium (<10 mg/L). CadA was primarily present as inclusion bodies, explaining the low activity. The activity was significantly improved by using lower cultivation temperatures and mineral medium, and this resulted in enhanced itaconate titres (240 mg/L). The itaconate titre was further increased by introducing citrate synthase and aconitase from Corynebacterium glutamicum and by deleting the genes encoding phosphate acetyltransferase and lactate dehydrogenase. These deletions in E. coli's central metabolism resulted in the accumulation of pyruvate, which is a precursor for itaconate biosynthesis. As a result, itaconate production in aerobic bioreactor cultures was increased up to 690 mg/L. The maximum yield obtained was 0.09 mol itaconate/mol glucose. Strategies for a further improvement of itaconate production are discussed.
authors.affiliation: Bioprocess Engineering, Wageningen University, Wageningen, The Netherlands, kiira.vuoristo@wur.nl.
authors.forename: Kiira S
authors.initials: KS
authors.lastname: Vuoristo
authors.forename: Astrid E
authors.initials: AE
authors.lastname: Mars
authors.forename: Jose Vidal
authors.initials: JV
authors.lastname: Sangra
authors.forename: Jan
authors.initials: J
authors.lastname: Springer
authors.forename: Gerrit
authors.initials: G
authors.lastname: Eggink
authors.forename: Johan P M
authors.initials: JP
authors.lastname: Sanders
authors.forename: Ruud A
authors.initials: RA
authors.lastname: Weusthuis
mesh_terms: D000154:Aconitate Hydratase / Q000235:genetics / Q000378:metabolism; D000332:Aerobiosis; D001230:Aspergillus / Q000201:enzymology / Q000235:genetics; D019149:Bioreactors; D002262:Carboxy-Lyases / Q000235:genetics / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D007770:L-Lactate Dehydrogenase / Q000235:genetics; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D008969:Molecular Sequence Data; D010709:Phosphate Acetyltransferase / Q000235:genetics; D017422:Sequence Analysis, DNA; D013386:Succinates / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D013386:Succinates; D007770:L-Lactate Dehydrogenase; D010709:Phosphate Acetyltransferase; D002950:Citrate (si)-Synthase; D002262:Carboxy-Lyases; C018742:aconitate decarboxylase; D000154:Aconitate Hydratase; C005229:itaconic acid