Aldehydes are useful in numerous applications, for example, as flavors and fragrances; however, microbial synthesis of aldehydes is hampered by their conversion to the less reactive alcohol or carboxylic acid.  We report the construction of an E. coli strain that can serve as a platform for the synthesis of aromatic aldehydes. Using benzoate as a model acid substrate, this engineered strain exhibited significantly lower endogenous conversion of the product benzaldehyde into benzyl alcohol relative to the wild-type MG1655 when both strains were expressing a recombinant carboxylic acid reductase. Several other strains that contained a subset of the six final deletions did not display significantly different reduction of benzaldehyde. We also examined the effect of overexpressing each of the six deleted genes individually on the conversion of the model compounds using the deletion strain. The results of individual overexpression experiments and experiments using deletion subset strains suggest that all deletions were required to observe the desired phenotype in the model product cases of benzaldehyde and vanillin. In the absence of wild-type aldehyde reductase activity and heterologous acid reductase activity, we also establish that aldehyde flux moves in the opposite (i.e., oxidation) direction, towards the corresponding acid rather than the alcohol. Finally, we demonstrate that the deletion strain can be used for production of vanillin from a natural bacterial metabolite in a similar manner as was shown in yeast.

Engineering <i>E. coli</i> for synthesis of aromatic aldehydes as products or intermediates under aerobic growth

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Engineering E. coli for synthesis of aromatic aldehydes as products or intermediates under aerobic growth