Some marine bacteria, such as Moritella marina, are able to produce certain amounts of the nutraceutical docosahexaenoic acid (DHA) thanks to a specifi c enzymatic complex called Pfa synthase. Moreover, Escherichia coli heterologously expressing this pfa gene cluster from M. marina is also able to produce DHA. The aim of this study was to find genetic or metabolic conditions to improve DHA production in E. coli or any other microorganism. First, we studied the eff ect of the antibiotic cerulenin on DHA production, which increased by 2-fold the DHA content of the cells. Then, we tested a series of single gene knock-out strains in order to alter the metabolic routes to optimize the biosynthesis of DHA. The best mutant strain carried the deletion of a specific gene, and showed a 3-fold increase compared to wild type strain. The combination of both cerulenin inhibition and this gene deletion rendered 12.75±1.21 mg DHA/g DCW, a 6.5-fold improvement compared to control strain. Furthermore, both strategies seem to have the same mechanism of action, in which the fatty acid synthesis in E. coli is affected in its fi rst catalytic step and allows the substrates to be used by the heterologous pathway to synthesize DHA. This data could be used for the biotechnological optimization in different organisms of DHA production and other synthetic pathways using the same competing substrate.

Resumen del póster presentado al XL Congreso de la Sociedad Española de Bioquímica y Biología Molecular (SEBBM), celebrado en Barcelona del 23 al 26 de octubre de 2017.

Peer reviewed