Production of Glucaric Acid from a Synthetic Pathway in Recombinant Escherichia coli

Abstract

ABSTRACT A synthetic pathway has been constructed for the production of glucuronic and glucaric acids from glucose in Escherichia coli . Coexpression of the genes encoding myo -inositol-1-phosphate synthase (Ino1) from Saccharomyces cerevisiae and myo -inositol oxygenase (MIOX) from mice led to production of glucuronic acid through the intermediate myo -inositol. Glucuronic acid concentrations up to 0.3 g/liter were measured in the culture broth. The activity of MIOX was rate limiting, resulting in the accumulation of both myo -inositol and glucuronic acid as final products, in approximately equal concentrations. Inclusion of a third enzyme, uronate dehydrogenase (Udh) from Pseudomonas syringae , facilitated the conversion of glucuronic acid to glucaric acid. The activity of this recombinant enzyme was more than 2 orders of magnitude higher than that of Ino1 and MIOX and increased overall flux through the pathway such that glucaric acid concentrations in excess of 1 g/liter were observed. This represents a novel microbial system for the biological production of glucaric acid, a “top value-added chemical” from biomass.