Improved production of the non-native cofactor F420 in Escherichia coli

The deazaflavin cofactor F-420 is a low-potential, two-electron redox cofactor produced by some Archaea and Eubacteria that is involved in methanogenesis and methanotrophy, antibiotic biosynthesis, and xenobiotic metabolism. However, it is not produced by bacterial strains commonly used for industrial biocatalysis or recombinant protein production, such as Escherichia coli, limiting our ability to exploit it as an enzymatic cofactor and produce it in high yield. Here we have utilized a genome-scale metabolic model of E. coli and constraint-based metabolic modelling of cofactor F-420 biosynthesis to optimize F-420 production in E. coli. This analysis identified phospho-enol pyruvate (PEP) as a limiting precursor for F-420 biosynthesis, explaining carbon source-dependent differences in productivity. PEP availability was improved by using gluconeogenic carbon sources and overexpression of PEP synthase. By improving PEP availability, we were able to achieve a similar to 40-fold increase in the space-time yield of F-420 compared with the widely used recombinant Mycobacterium smegmatis expression system. This study establishes E. coli as an industrial F-420-production system and will allow the recombinant in vivo use of F-420-dependent enzymes for biocatalysis and protein engineering applications.

Automated summary

F-420 is a crucial cofactor produced by some Archaea and Eubacteria, but not by commonly used industrial bacteria like E. coli. By utilizing metabolic modeling and optimizing precursor availability, researchers were able to improve F-420 production in E. coli by 40-fold, establishing it as an industrial production system and enabling the use of F-420-dependent enzymes for biocatalysis and protein engineering.