Non-redundant functionality of Lactiplantibacillus plantarum phospho-ß-glucosidases revealed by carbohydrate utilization signatures associated to pbg2 and pbg4 gene mutants.

AIM: To increase our knowledge on the functionality of 6-phospho-ß-glucosidases linked to phosphoenolpyruvate-dependent phosphotransferase systems (PTS) that are encountered in high redundancy in the Lactiplantibacillus plantarum WCFS1 genome. METHODS AND RESULTS: Two L. plantarum WCFS1 gene mutants that lacked one of the 6-phospho-ß-glucosidases, ∆pbg2 (or ∆lp_0906) or ∆pbg4 (or ∆lp_2777) were constructed and the metabolic impact of these mutations assessed by high-throughput phenotyping (Omnilog). The ∆pbg2 mutant displayed a reduced metabolic performance, having lost the capacity to utilize 20 out of 57 carbon (C)-sources used by the wild-type strain. Conversely, the ∆pbg4 mutant conserved the capacity to metabolize most of the C-sources preferred by the wild type strain. This mutant utilized 56 C-sources albeit the range of substrates used and hence its metabolic profiling differed from that of the WCFS1 strain. The ∆pbg2 mutant notably reduced or abolished the capacity to metabolize substrates related to pentose and glucoronate interconversions and was unable to assimilate fatty acids or nucleosides as sole C-sources for growth. The ∆pbg4 mutant acquired the capacity to utilize efficiently glycogen, indicating an efficient supply of glucose from this source. CONCLUSION: Lactiplantibacillus plantarum gene mutants that lack individual 6-phospho-ß-glucosidases display very different carbohydrate utilization signatures showing that these enzymes can be crucial to determine the capacity of L. plantarum to consume different C-sources and hence for the nutrition and physiology of this microorganism.

Unravelling the Reduction Pathway as an Alternative Metabolic Route to Hydroxycinnamate Decarboxylation in Lactobacillus plantarum.

Lactobacillus plantarum is the lactic acid bacterial species most frequently found in plant-food fermentations where hydroxycinnamic acids are abundant. L. plantarum efficiently decarboxylates these compounds and also reduces them, yielding substituted phenylpropionic acids. Although the reduction step is known to be induced by a hydroxycinnamic acid, the enzymatic machinery responsible for this reduction pathway has not been yet identified and characterized. A previous study on the transcriptomic response of L. plantarum to p-coumaric acid revealed a marked induction of two contiguous genes, lp_1424 and lp_1425, encoding putative reductases. In this work, the disruption of these genes abolished the hydroxycinnamate reductase activity of L. plantarum, supporting their involvement in such chemical activity. Functional in vitro studies revealed that Lp_1425 (HcrB) exhibits hydroxycinnamate reductase activity but was unstable in solution. In contrast, Lp_1424 (HcrA) was inactive but showed high stability. When the hcrAB genes were co-overexpressed, the formation of an active heterodimer (HcrAB) was observed. Since L. plantarum reductase activity was only observed on hydroxycinnamic acids (o-coumaric, m-coumaric, p-coumaric, caffeic, ferulic, and sinapic acids), the presence of a hydroxyl group substituent on the benzene ring appears to be required for activity. In addition, hydroxycinnamate reductase activity was not widely present among lactic acid bacteria, and it was associated with the presence of hcrAB genes. This study revealed that L. plantarum hydroxycinnamate reductase is a heterodimeric NADH-dependent coumarate reductase acting on a carbon-carbon double bond.IMPORTANCELactobacillus plantarum is a bacterial species frequently found in the fermentation of vegetables where hydroxycinnamic acids are present. The bacterial metabolism on these compounds during fermentation plays a fundamental role in the biological activity of hydroxycinnamates. L. plantarum strains exhibit an as yet unknown reducing activity, transforming hydroxycinnamates to substituted phenylpropionic acids, which possess higher antioxidant activity than their precursors. The protein machinery involved in hydroxycinnamate reduction, HcrAB, was genetically identified and characterized. The heterodimeric NADH-dependent coumarate reductase HcrAB described in this work provides new insights on the L. plantarum metabolic response to counteract the stressful conditions generated by food phenolics.

Differential Gene Expression by Lactobacillus plantarum WCFS1 in Response to Phenolic Compounds Reveals New Genes Involved in Tannin Degradation.

Lactobacillus plantarum is a lactic acid bacterium that can degrade food tannins by the successive action of tannase and gallate decarboxylase enzymes. In the L. plantarum genome, the gene encoding the catalytic subunit of gallate decarboxylase (lpdC, or lp_2945) is only 6.5 kb distant from the gene encoding inducible tannase (L. plantarumtanB [tanBLp ], or lp_2956). This genomic context suggests concomitant activity and regulation of both enzymatic activities. Reverse transcription analysis revealed that subunits B (lpdB, or lp_0271) and D (lpdD, or lp_0272) of the gallate decarboxylase are cotranscribed, whereas subunit C (lpdC, or lp_2945) is cotranscribed with a gene encoding a transport protein (gacP, or lp_2943). In contrast, the tannase gene is transcribed as a monocistronic mRNA. Investigation of knockout mutations of genes located in this chromosomal region indicated that only mutants of the gallate decarboxylase (subunits B and C), tannase, GacP transport protein, and TanR transcriptional regulator (lp_2942) genes exhibited altered tannin metabolism. The expression profile of genes involved in tannin metabolism was also analyzed in these mutants in the presence of methyl gallate and gallic acid. It is noteworthy that inactivation of tanR suppresses the induction of all genes overexpressed in the presence of methyl gallate and gallic acid. This transcriptional regulator was also induced in the presence of other phenolic compounds, such as kaempferol and myricetin. This study complements the catalog of L. plantarum expression profiles responsive to phenolic compounds, which enable this bacterium to adapt to a plant food environment.IMPORTANCELactobacillus plantarum is a bacterial species frequently found in the fermentation of vegetables when tannins are present. L. plantarum strains degrade tannins to the less-toxic pyrogallol by the successive action of tannase and gallate decarboxylase enzymes. The genes encoding these enzymes are located close to each other in the chromosome, suggesting concomitant regulation. Proteins involved in tannin metabolism and regulation, such GacP (gallic acid permease) and TanR (tannin transcriptional regulator), were identified by differential gene expression in knockout mutants with mutations in genes from this region. This study provides insights into the highly coordinated mechanisms that enable L. plantarum to adapt to plant food fermentations.

Molecular adaptation of Lactobacillus plantarum WCFS1 to gallic acid revealed by genome-scale transcriptomic signature and physiological analysis.

BACKGROUND: Gallic acid (GA) is a model hydroxybenzoic acid that occurs esterified in the lignocellulosic biomass of higher plants. GA displays relevant biological activities including anticancer properties. Owing to its antimicrobial and cellulase-inhibiting activities, GA also imposes constraints to the fermentability of lignocellulosic hydrolysates. In depth-knowledge of the mechanisms used by tolerant microorganisms to adapt to hydroxybenzoic acids would be a step forward to improve the bioavailability of GA or select/engineer production hosts with improved metabolic traits for the bioconversion of pretreated lignocellulosic biomass. RESULTS: Whole genome transcriptional profiling using DNA microarrays was used to characterize the molecular response of Lactobacillus plantarum WCFS1 to GA. Expression levels of 14 and 40 genes were differentially regulated at 1.5 and 15 mM GA, respectively. The transcriptomic analysis identified a marked induction of genes with confirmed or related roles to gastrointestinal survival, the repression of genes coding for certain ABC-type transporters and modulation of genes involved in the control of intracellular ammonia levels, among other responses. Most notably, a core set of genes dedicated to produce GA from polyphenols (tanB Lp ), decarboxylate GA to pyrogallol (lpdB, lpdC and lpdD) and transport functions (lp_2943) was highly overexpressed at both GA concentrations. Correspondingly, resting cells of strain WCFS1 induced by GA, but not their non-induced controls, produced pyrogallol. Gene expression and organization of genes involved in GA metabolism suggested a chemiosmotic mechanism of energy generation. Resting cells of L. plantarum induced by GA generated a membrane potential and a pH gradient across the membrane immediately upon addition of GA. Altogether, transcriptome profiling correlated with physiological observations indicating that a proton motive force could be generated during GA metabolism as a result of electrogenic GA uptake coupled with proton consumption by the intracellular gallate decarboxylase. CONCLUSIONS: The combination of transcriptome and physiological analyses revealed versatile molecular mechanisms involved in the adaptation of L. plantarum to GA. These data provide a platform to improve the survival of Lactobacillus in the gut. Our data may also guide the selection/engineering of microorganisms that better tolerate phenolic inhibitors present in pretreated lignocellulosic feedstocks.

Genetic and biochemical approaches towards unravelling the degradation of gallotannins by Streptococcus gallolyticus.

BACKGROUND: Herbivores have developed mechanisms to overcome adverse effects of dietary tannins through the presence of tannin-resistant bacteria. Tannin degradation is an unusual characteristic among bacteria. Streptococcus gallolyticus is a common tannin-degrader inhabitant of the gut of herbivores where plant tannins are abundant. The biochemical pathway for tannin degradation followed by S. gallolyticus implies the action of tannase and gallate decarboxylase enzymes to produce pyrogallol, as final product. From these proteins, only a tannase (TanBSg) has been characterized so far, remaining still unknown relevant proteins involved in the degradation of tannins. RESULTS: In addition to TanBSg, genome analysis of S. gallolyticus subsp. gallolyticus strains revealed the presence of an additional protein similar to tannases, TanASg (GALLO_0933). Interestingly, this analysis also indicated that only S. gallolyticus strains belonging to the subspecies "gallolyticus" possessed tannase copies. This observation was confirmed by PCR on representative strains from different subspecies. In S. gallolyticus subsp. gallolyticus the genes encoding gallate decarboxylase are clustered together and close to TanBSg, however, TanASg is not located in the vicinity of other genes involved in tannin metabolism. The expression of the genes enconding gallate decarboxylase and the two tannases was induced upon methyl gallate exposure. As TanBSg has been previously characterized, in this work the tannase activity of TanASg was demonstrated in presence of phenolic acid esters. TanASg showed optimum activity at pH 6.0 and 37°C. As compared to the tannin-degrader Lactobacillus plantarum strains, S. gallolyticus presented several advantages for tannin degradation. Most of the L. plantarum strains possessed only one tannase enzyme (TanBLp), whereas all the S. gallolytcius subsp. gallolyticus strains analyzed possesses both TanASg and TanBSg proteins. More interestingly, upon methyl gallate induction, only the tanB Lp gene was induced from the L. plantarum tannases; in contrast, both tannase genes were highly induced in S. gallolyticus. Finally, both S. gallolyticus tannase proteins presented higher activity than their L. plantarum counterparts. CONCLUSIONS: The specific features showed by S. gallolyticus subsp. gallolyticus in relation to tannin degradation indicated that strains from this subspecies could be considered so far the best bacterial cellular factories for tannin degradation.

Revised Aspects into the Molecular Bases of Hydroxycinnamic Acid Metabolism in Lactobacilli.

Hydroxycinnamic acids (HCAs) are phenolic compounds produced by the secondary metabolism of edible plants and are the most abundant phenolic acids in our diet. The antimicrobial capacity of HCAs is an important function attributed to these phenolic acids in the defense of plants against microbiological threats, and bacteria have developed diverse mechanisms to counter the antimicrobial stress imposed by these compounds, including their metabolism into different microbial derivatives. The metabolism of HCAs has been intensively studied in Lactobacillus spp., as the metabolic transformation of HCAs by these bacteria contributes to the biological activity of these acids in plant and human habitats or to improve the nutritional quality of fermented foods. The main mechanisms known to date used by Lactobacillus spp. to metabolize HCAs are enzymatic decarboxylation and/or reduction. Here, recent advances in the knowledge regarding the enzymes that contribute to these two enzymatic conversions, the genes involved, their regulation and the physiological significance to lactobacilli are reviewed and critically discussed.

Molecular Responses of Lactobacilli to Plant Phenolic Compounds: A Comparative Review of the Mechanisms Involved.

Lactobacilli are well-studied bacteria that can undergo oxidative selective pressures by plant phenolic compounds (PPCs) in plants, during some food fermentations or in the gastrointestinal tract of animals via dietary inputs. Lactobacilli are known to be more tolerant to PPCs than other bacterial groups and, therefore, must have mechanisms to cope with the effects of these metabolites. In this review, we intend to present what is currently known about the basics beyond the responses of Lactobacillus spp. to individual PPCs. We review the molecular mechanisms that are engaged in the PPC-modulated responses studied to date in these bacteria that have been mainly characterized by system-based strategies, and we discuss their differences and similarities. A wide variety of mechanisms are induced to increase the oxidative stress response highlighting the antimicrobial nature of PPCs. However other uncovered mechanisms that are involved in the response to these compounds are reviewed, including the capacity of PPCs to modulate the expression of molecular functions used by lactobacilli to adapt to host environments. This shows that these phytochemicals can act as more than just antimicrobial agents in the dual interaction with lactobacilli.

Transcriptomic Evidence of Molecular Mechanisms Underlying the Response of Lactobacillus Plantarum WCFS1 to Hydroxytyrosol.

Abstract: This study was aimed to gain new insights into the molecular mechanisms used by Lactobacillus plantarum WCFS1 to respond to hydroxytyrosol (HXT), one of the main and health-relevant plant phenolics present in olive oil. To this goal, whole genome transcriptomic profiling was used to better understand the contribution of differential gene expression in the adaptation to HXT by this microorganism. The transcriptomic profile reveals an HXT-triggered antioxidant response involving genes from the ROS (reactive oxygen species) resistome of L. plantarum, genes coding for H2S-producing enzymes and genes involved in the response to thiol-specific oxidative stress. The expression of a set of genes involved in cell wall biogenesis was also upregulated, indicating that this subcellular compartment was a target of HXT. The expression of several MFS (major facilitator superfamily) efflux systems and ABC-transporters was differentially affected by HXT, probably to control its transport across the membrane. L. plantarum transcriptionally reprogrammed nitrogen metabolism and involved the stringent response (SR) to adapt to HXT, as indicated by the reduced expression of genes involved in cell proliferation or related to the metabolism of (p)ppGpp, the molecule that triggers the SR. Our data have identified, at genome scale, the antimicrobial mechanisms of HXT action as well as molecular mechanisms that potentially enable L. plantarum to cope with the effects of this phenolic compound.

Multiple control of the acetate pathway in Lactococcus lactis under aeration by catabolite repression and metabolites.

To explore the factors controlling metabolite formation under aeration in Lactococcus lactis, metabolic patterns, enzymatic activities, and transcriptional profiles of genes involved in the aerobic pathway for acetate anabolism were compared between a parental L. lactis strain and its NADH-oxidase-overproducer derivative. Deregulated catabolite repression mutans in the ccpA or pstH genes, encoding CcpA or its co-activator HPr, respectively, were compared with a parental strain, as well. Although the NADH-oxidase activity was derepressed in ccpA, but not in the pstH background, a mixed fermentation was displayed by either mutant, with a higher acetate production in the pstH variant. Moreover, transcription of genes encoding phosphotransacetylase and acetate kinase were derepressed, and the corresponding enzymatic activities increased, in both catabolite repression mutants. These results and the dependence on carbon source for acetate production in the NADH-oxidase-overproducer support the conclusion that catabolite repression, rather than NADH oxidation, plays a critical role to control acetate production. Furthermore, fructose 1,6-bisphosphate influenced the in vitro phosphotransacetylase and acetate kinase activities, while the former was sensitive to diacetyl. Our study strongly supports the model that, under aerobic conditions, the homolactic fermentation in L. lactis MG1363 is maintained by CcpA-mediated repression of mixed acid fermentation.

Oleuropein Transcriptionally Primes Lactobacillus plantarum to Interact With Plant Hosts.

Oleuropein (OLE) is a secoiridoid unique to Oleaceae known to play a role in the plant-herbivore interaction. However, it is not clear how this molecule is induced to mediate plant responses to microbes and how microbes, in turn, withstand with OLE. To better understand how OLE affects the plant-microbe interaction, the contribution of differential gene expression in the adaptation to OLE was characterized by whole genome transcriptional profiling in Lactobacillus plantarum, a bacterium associated to the olive. OLE downregulated functions associated to rapid growth, remodeled membrane phospholipid biosynthesis pathways and markedly repressed the expression of several ABC transporters from L. plantarum. Genes encoding the plantaricin and lamABDCA quorum-sensing (QS) systems were down-regulated indicating the potential of OLE as a QS-antagonist. Notably, OLE diminished the expression of a set of genes encoding inmunomodulatory components and reoriented metabolic pathways to increase protein acetylation, probably to attenuate plant immunity. Responses were also triggered to repress the transport of acetoin and to buffer reactive oxygen species accumulation, two signals involved in plant development. The results suggest that OLE could act as a signaling molecule in the plant-microbe interaction and facilitate the accommodation of beneficial microbes such as L. plantarum by the plant host, via controlled expression of bacterial molecular players involved in this reciprocal interplay.

Transcriptome-Based Analysis in Lactobacillus plantarum WCFS1 Reveals New Insights into Resveratrol Effects at System Level.

SCOPE: This study was undertaken to expand our insights into the mechanisms involved in the tolerance to resveratrol (RSV) that operate at system-level in gut microorganisms and advance knowledge on new RSV-responsive gene circuits. METHODS AND RESULTS: Whole genome transcriptional profiling was used to characterize the molecular response of Lactobacillus plantarum WCFS1 to RSV. DNA repair mechanisms were induced by RSV and responses were triggered to decrease the load of copper, a metal required for RSV-mediated DNA cleavage, and H2 S, a genotoxic gas. To counter the effects of RSV, L. plantarum strongly up- or downregulated efflux systems and ABC transporters pointing to transport control of RSV across the membrane as a key mechanism for RSV tolerance. L. plantarum also downregulated tRNAs, induced chaperones, and reprogrammed its transcriptome to tightly control ammonia levels. RSV induced a probiotic effector gene and a likely deoxycholate transporter, two functions that improve the host health status. CONCLUSION: Our data identify novel protective mechanisms involved in RSV tolerance operating at system level in a gut microbe. These insights could influence the way RSV is used for a better management of gut microbial ecosystems to obtain associated health benefits.

Transcriptional Reprogramming at Genome-Scale of Lactobacillus plantarum WCFS1 in Response to Olive Oil Challenge.

Dietary fats may exert selective pressures on Lactobacillus species, however, knowledge on the mechanisms of adaptation to fat stress in these organisms is still fragmentary. This study was undertaken to gain insight into the mechanisms of adaptation of Lactobacillus plantarum WCFS1 to olive oil challenge by whole genome transcriptional profiling using DNA microarrays. A set of 230 genes were differentially expressed by L. plantarum WCFS1 to respond to this vegetable oil. This response involved elements typical of the stringent response, as indicated by the induction of genes involved in stress-related pathways and downregulation of genes related to processes associated with rapid growth. A set of genes involved in the transport and metabolism of compatible solutes were downregulated, indicating that this organism does not require osmoprotective mechanisms in presence of olive oil. The fatty acid biosynthetic pathway was thoroughly downregulated at the transcriptional level, which coincided with a diminished expression of genes controlled by this pathway in other organisms and that are required for the respiratory function, pyruvate dehydrogenase activity, RNA processing and cell size setting. Finally, a set of genes involved in host-cell signaling by L. plantarum were differentially regulated indicating that olive oil can influence the expression of metabolic traits involved in the crosstalk between this bacterium and the host.

Bioactive compounds produced by gut microbial tannase: implications for colorectal cancer development.

The microorganisms in the human gastrointestinal tract have a profound influence on the transformation of food into metabolites which can impact human health. Gallic acid (GA) and pyrogallol (PG) are bioactive compounds displaying diverse biological properties, including carcinogenic inhibiting activities. However, its concentration in fruits and vegetables is generally low. These metabolites can be also generated as final products of tannin metabolism by microbes endowed with tannase, which opens up the possibility of their anti-cancer potential being increased. Patients with colorectal cancer (CRC) display an imbalanced gut microbiota respect to healthy population. The recent use of next generation sequencing technologies has greatly improved knowledge of the identity of bacterial species that colonize non-tumorous and tumorous tissues of CRC patients. This information provides a unique opportunity to shed light on the role played by gut microorganisms in the different stages of this disease. We here review the recently published gut microbiome associated to CRC patients and highlight tannase as an underlying gene function of bacterial species that selectively colonize tumorous tissues, but not adjacent non-malignant tissues. Given the anti-carcinogenic roles of GA and PG produced by gut tannin-degrading bacteria, we provide an overview of the possible consequences of this intriguing coincidence for CRC development.

Genome-wide transcriptomic responses of a human isolate of Lactobacillus plantarum exposed to p-coumaric acid stress.

SCOPE: To advance knowledge of the stress tolerance mechanisms of a probiotic Lactobacillus plantarum strain to dietary hydroxycinnamic acids and the role of gut commensal microorganisms in the bioactivation of polyphenols. METHODS AND RESULTS: To understand how gut commensal microorganisms tolerate toxicity of hydroxycinnamic acids and bioactivate these compounds, we used whole genome transcriptional profiling to characterize the response of a L. plantarum human isolate during challenge with p-coumaric acid (p-CA). The transcriptional profile reveals a massive induction of genes involved in stress resistance and detoxification-related functions and a global shutdown of growth-associated processes. A specific oxidative stress response, including a large reshape of nitrogen metabolism toward methionine production, was induced, probably to counteract a p-CA-induced oxidative protein stress. The transcriptional datasets revealed overlapping behaviors with the response of L. plantarum to the gut environment. CONCLUSION: Contact with p-CA triggers responses that would be potentially beneficial for the intestinal function such as detoxification of dietary hydroxycinnamic acids and induction of a marked antioxidant response. Elicited responses indicated that contact with p-CA could provide preparedness to L. plantarum for adaptation to the gut environment. This knowledge facilitates the way to design methods to improve probiotic cell survival in this habitat.

Response of a Lactobacillus plantarum human isolate to tannic acid challenge assessed by proteomic analyses.

SCOPE: To gain insight on the mechanisms used by intestinal bacteria to adapt and resist the antimicrobial action of dietary tannins and identify targets for tannic acid in Lactobacillus plantarum. METHODS AND RESULTS: A proteomic analysis of an L. plantarum human isolate exposed to the tannic acid challenge was undertaken. Tannic acid targeted proteins involved in outstanding processes for bacterial stress resistance including cyclopropanation of membrane lipids, stress response at population scale and maintenance of cell shape. To respond to this aggression, tannic acid-misfit cells of L. plantarum challenged with tannic acid reorganized their metabolic capacity to economize energy and express proteins involved in oxidative stress defense and cell wall biogenesis, indicating that the injury incurred by tannic acid was based on oxidative damage and disruption of the cell envelope. The induction of 3-octaprenyl-4-hydroxybenzoate carboxy-lyase, which is sensitive to changes in redox conditions and involved in ubiquinone biosynthesis in other bacteria, suggests for a tannic acid-induced redox imbalance. CONCLUSION: The results reveal the adaptation of a gastrointestinal isolate of L. plantarum to tannic acid and identify antibacterial targets for this dietary compound. This provides the basis for the selection of tannin-resistant microorganisms and their use to obtain health benefits from tannin-containing diets.

Delaying effect of a wine Lactobacillus plantarum strain on the coloration and xanthylium pigment formation occurring in (+)-catechin and (-)-epicatechin wine model solutions.

This article reports for the first time on the capacity of a wine Lactobacillus plantarum strain to alter the oxidative coloration of (+)-catechin and (-)-epicatechin hydroethanolic wine model solutions in the presence of Fe(2+) as catalyst. The time course of color development and pigment formation in the solutions was tracked over 42 days. The pigments formed were characterized as xanthylium structures regardless of the flavanol isomer present in the solution. The solutions supplied with Lactobacillus plantarum RM71 were oxidized at a slower rate, and consequently, its final color was less than that in the controls. The formation of both (+)-catechin and (-)-epicatechin-derived xanthylium pigments was also delayed over time in the presence of the bacterium compared to their respective cell-free controls. The delaying effects provided by L. plantarum on the oxidative coloration and the generation of xanthylium-derived pigments were more pronounced for the (-)-epicatechin than for the (+)-catechin model solutions. In view of these results and given that L. plantarum is naturally present in winemaking and generally recognized as a safe microorganism, the potential application of this bacterium as an antibrowning agent for wine is now opened.

Food phenolics and lactic acid bacteria.

Phenolic compounds are important constituents of food products of plant origin. These compounds are directly related to sensory characteristics of foods such as flavour, astringency, and colour. In addition, the presence of phenolic compounds on the diet is beneficial to health due to their chemopreventive activities against carcinogenesis and mutagenesis, mainly due to their antioxidant activities. Lactic acid bacteria (LAB) are autochthonous microbiota of raw vegetables. To get desirable properties on fermented plant-derived food products, LAB has to be adapted to the characteristics of the plant raw materials where phenolic compounds are abundant. Lactobacillus plantarum is the commercial starter most frequently used in the fermentation of food products of plant origin. However, scarce information is still available on the influence of phenolic compounds on the growth and viability of L. plantarum and other LAB species. Moreover, metabolic pathways of biosynthesis or degradation of phenolic compounds in LAB have not been completely described. Results obtained in L. plantarum showed that L. plantarum was able to degrade some food phenolic compounds giving compounds influencing food aroma as well as compounds presenting increased antioxidant activity. Recently, several L. plantarum proteins involved in the metabolism of phenolic compounds have been genetically and biochemically characterized. The aim of this review is to give a complete and updated overview of the current knowledge among LAB and food phenolics interaction, which could facilitate the possible application of selected bacteria or their enzymes in the elaboration of food products with improved characteristics.