The metabolism of ferulic acid via 4-vinylguaiacol to vanillin by Enterobacter sp. Px6-4 isolated from Vanilla root

This study reports a bacterium from Vanilla roots with the ability to utilize ferulic acid as the sole carbon source to produce vanillin. The strain was identified as Enterobacter sp. Px6-4 based on its 16S rDNA sequence and biochemical characteristics. The primary metabolites using ferulic acid as the sole carbon source include 4-vinylguaiacol, vanillin as well as other related chemicals, all of which share the same guaiacol-carbon-skeleton. Based on structural analyses of non-volatile compounds in the culture filtrate of this strain, two putative novel metabolites were isolated and identified. These results allowed us to propose the possible metabolic pathway leading from ferulic acid to vanillin via 4-vinylguaiacol. Our experiments elucidated for the first time of a ferulic acid metabolism via decarboxylation to produce 4-vinylguaiacol and a further conversion to vanillin in Enterobacter sp. Px6-4.