Involved in the non-oxidative decarboxylation and detoxification of phenolic derivatives under both aerobic and anaerobic conditions (PubMed:10517592, PubMed:15979273). Phenolic acid decarboxylase that catalyzes the reversible decarboxylation of vanillate (PubMed:10517592, PubMed:15979273). H(+) + vanillate = CO2 + guaiacol Binds 1 prenylated FMN (prenyl-FMN) per subunit. By vanillate. It is not known, if phenolic acid decarboxylase forms a complex composed of VdcB, VdcC and VdcD. The term subunit is often used in reference to the operon, however there is no experimental evidence to prove the existence of the complex. Belongs to the UbiD family. YclC subfamily.