Metabolic engineering of Escherichia coli for agmatine production.

Abstract

Agmatine is a kind of important biogenic amine. The chemical synthesis route is not a desirable choice for industrial production of agmatine. To date, there are no reports on the fermentative production of agmatine by microorganism. In this study, the base Escherichia coli strain AUX4 (JM109 ∆speC ∆speF ∆speB ∆argR) capable of excreting agmatine into the culture medium was first constructed by sequential deletions of the speC and speF genes encoding the ornithine decarboxylase isoenzymes, the speB gene encoding agmatine ureohydrolase and the regulation gene argR responsible for the negative control of the arg regulon. The speA gene encoding arginine decarboxylase harboured by the pKK223-3 plasmid was overexpressed in AUX4, resulting in the engineered strain AUX5. The batch and fed-batch fermentations of the AUX5 strain were conducted in a 3-L bioreactor, and the results showed that the AUX5 strain was able to produce 1.13g agmatine L-1 with the yield of 0.11g agmatine g-1 glucose in the batch fermentation and the fed-batch fermentation of AUX5 allowed the production of 15.32g agmatine L-1 with the productivity of 0.48g agmatine L-1 h-1, demonstrating the potential of E.coli as an industrial producer of agmatine.