Aconitate isomerase (AI; EC 22.214.171.124) catalyzes the isomerization of cis-aconitic acid and trans-aconitic acid. Since trans-aconitic acid is an unsaturated organic acid, effective and environmentally benign processes are needed for trans-aconitic acid production. Here, the genes encoding AI from Pseudomonas sp. WU-0701 and aconitate hydratase (AH; EC 126.96.36.199) from Escherichia coli W3110, catalyzing the dehydration of citric acid and formation of cis-aconitic acid, were co-expressed in E. coli Rosetta 2(DE3). The recombinant E. coli cells were used as biocatalysts for trans-aconitic acid production from citric acid by whole-cell reaction. The optimal conditions were 37°C and pH 7.0. Using recombinant E. coli cells as biocatalysts for the whole-cell reaction, 91 mM trans-aconitic acid was produced from 400 mM citric acid within 120 min. This is the first report describing a solvent- and harmful reagent-free system for trans-aconitic acid bioproduction usable under moderate conditions.
ASJC Scopus subject areas