Knockout of thep-Coumarate Decarboxylase Gene fromLactobacillus plantarumReveals the Existence of Two Other Inducible Enzymatic Activities Involved in Phenolic Acid Metabolism

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Lactobacillus plantarumNC8 contains apdcgene coding forp-coumaric acid decarboxylase activity (PDC). A food grade mutant, designated LPD1, in which the chromosomalpdcgene was replaced with the deletedpdcgene copy, was obtained by a two-step homologous recombination process using an unstable replicative vector. The LPD1 mutant strain remained able to weakly metabolizep-coumaric and ferulic acids into vinyl derivatives or into substituted phenyl propionic acids. We have shown thatL. plantarumhas a second acid phenol decarboxylase enzyme, better induced with ferulic acid than withp-coumaric acid, which also displays inducible acid phenol reductase activity that is mostly active when glucose is added. Those two enzymatic activities are in competition forp-coumaric and ferulic acid degradation, and the ratio of the corresponding derivatives depends on induction conditions. Moreover, PDC appeared to decarboxylate ferulic acid in vitro with a specific activity of about 10 nmol · min−1· mg−1in the presence of ammonium sulfate. Finally, PDC activity was shown to confer a selective advantage on LPNC8 grown in acidic media supplemented withp-coumaric acid, compared to the LPD1 mutant devoid of PDC activity.

This publication has 44 references indexed in Scilit: