Biosynthesis of Glucaric Acid by Recombinant Strain of Escherichia coli Expressing Two Different Urinate Dehydrogenases

D-glucaric acid is an important bio-based building block of polymers and is a high value-added chemical that can be used in a variety of applications. In the present study, the Udh target genes from Pseudomonas putida and Pseudomonas syringae were used together to construct the expression vector pETDuet-2 × Udh. The transformants of BL21 (DE3) with vector pETDuet-2 × Udh were applied to produce glucaric acid from glucuronic acid. After optimizing the induction conditions, the highest Udh expression was achieved when 0.4 mmol·L−1 isopropyl-β-d–thiogalactoside (IPTG) was added to the cell cultures at an OD600 value of 0.6 followed by culturing at 26 °C for 6 h. The production of glucaric acid substantially reached 5.24 ± 0.015 g·L−1 in fed-batch cultures in a 30 L tank. In the present study, a new system for glucaric acid production was established, which was more economic and friendly to the environment.