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

Abstract

Lactobacillus plantarum NC8 contains a pdc gene coding for p-coumaric acid decarboxylase activity (PDC). A food grade mutant, designated LPD1, in which the chromosomal pdc gene was replaced with the deleted pdc gene copy, was obtained by a two-step homologous recombination process using an unstable replicative vector. The LPD1 mutant strain remained able to weakly metabolize p-coumaric and ferulic acids into vinyl derivatives or into substituted phenyl propionic acids. We have shown that L. plantarum has a second acid phenol decarboxylase enzyme, better induced with ferulic acid than with p-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 for p-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 ⅐ min ؊1 ⅐ mg ؊1 in the presence of ammonium sulfate. Finally, PDC activity was shown to confer a selective advantage on LPNC8 grown in acidic media supplemented with p-coumaric acid, compared to the LPD1 mutant devoid of PDC activity.

Molecular characterization of the phenolic acid metabolism in the lactic acid bacteria Lactobacillus plantarum

“…In order to investigate alternate pathways for phenolic acid degradation, a L. plantarum strain deficient in PDC activity was constructed [2]. The procedure used led to a completely stable chromosomal deletion within the pdc gene through a two-step homologous recombination process.…”

“…Kinetic reactions were started by addition of the substrate and samples were diluted in Stop buffer. Phenolic acid consumption and derivative production was monitored by UV-spectrophotometry scanning (from 180 to 330 nm using quartz cuvettes in a Beckman DU600 spectrophotometer) as previously described [2,5,13]. bacteria grown with these substrates suggesting that this activity was inducible.…”

“…The mutant strain was named LPD1. Southern blotting and DNA sequencing were performed on the LPD1 DNA to confirm the deletion [2].…”

Rose Hip and Lactobacillus plantarum DSM 9843 Reduce Ischemia/Reperfusion Injury in the Mouse Colon

“…Most Lactobacillus spp. are unable to degrade polyphenols, but strains of the closely related species Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus paraplantarum possess tannase activity (14) -tannins are naturally occurring water soluble polyphenols -and metabolise phenolic acids (15).…”

Inducible Metabolism of Phenolic Acids inPediococcus pentosaceusIs Encoded by an Autoregulated Operon Which Involves a New Class of Negative Transcriptional Regulator

“…Chambel et al (11) showed that Saccharomyces cerevisiae induced the expression of the H ϩ -ATPase pumps in response to inhibitory concentrations of cinnamic acid. In a previous work (4), we demonstrated that the ubiquitous lactic acid bacterium Lactobacillus plantarum exhibits inducible pcoumaric acid decarboxylase (PDC) activity, which converts p-coumaric acid into 4-vinyl phenol, a less toxic compound. We also showed that L. plantarum PDC activity confers a selective advantage for growth in p-coumaric acid-supplemented medium and therefore proposed that PDC synthesis could be considered as a stress response induced by phenolic acid toxicity.…”