Catabolic System of 5-Formylferulic Acid, a Downstream Metabolite of a β-5-Type Lignin-Derived Dimer, in SYK-6.

SYK-6 can assimilate various lignin-derived aromatic compounds, including a β-5-type (phenylcoumaran-type) dimer, dehydrodiconiferyl alcohol (DCA). SYK-6 converts DCA to a stilbene-type intermediate via multiple reaction steps and then to vanillin and 5-formylferulic acid (FFA). Here, we first elucidated the catabolic pathway of FFA, which is the only unknown pathway in DCA catabolism.