Microbial production of glutaconic acid via extradiol ring cleavage of catechol

BACKGROUND: Glutaconic acid (GA), a potential precursor for nylons and biodegradable polyesters, can hardly be produced by microorganisms in nature. In this study, a metabolic engineering method was used to design a novel artificial pathway in Escherichia coli for GA production by connecting catechol biosynthesis and its extradiol cleavage degradation pathway. RESULTS: Results of enzyme assays showed the k(cat) value of C23O (catechol 2, 3-dioxygenase) toward catechol was 101.6 +/- 2.0 s(-1), and the k(cat) value of DmpC (2-hydroxymuconic semialdehyde dehydrogenase) toward 2-hydroxymuconic semialdehyde was 11.1 +/- 0.6 s(-1). The enzymes of full pathway were then split into four modules according to their various activities. After feeding experiments, the full pathway was introduced into E. coli strain BW25113, and the production of GA reached 18.1 +/- 1.2 mg L-1. After two genes of the pathway were incorporated into the chromosome, the resultant strain exhibited improved cell growth, and the titer of GA reached 35.3 +/- 1.8 mg L-1. CONCLUSIONS: The catalytic parameters of C23O and DmpC were tested and used for module assembling. Integration of genes in the pathway alleviated the metabolic burden of strain and resulted in higher production of GA. Moreover, this is the first report demonstrating the de novo biosynthesis of GA via extradiol ring cleavage of catechol from simple carbon sources in E. coli. (C) 2017 Society of Chemical Industry