Isolation and Characterization of a Resveratrol-Metabolizing Human Gut Bacterium

Abstract Resveratrol undergoes biotransformation by gut bacteria, producing metabolites that can contribute to its bioactive potential. Yet the few known intestinal strains contributing to this interaction mainly belong to Coriobacteriia, with only a fraction of them isolated from human feces. Human stool samples (n = 8) were screened, with analytes quantified under liquid chromatography–mass spectrometry. Only one sample produced 3,4′-dihydroxy-trans-stilbene, whereas dihydroresveratrol was detected in all samples, reflecting interindividual variation in resveratrol metabolism across individuals. A bacterium displaying resveratrol-metabolizing capabilities was isolated, producing dihydroresveratrol. Whole genome sequencing identified the isolate as Enterococcus lactis UMA_R1. Time-course analysis revealed that the isolate commenced resveratrol metabolism upon entering the stationary growth phase at 4 h. Broader polyphenol substrate testing suggests that E. lactis UMA_R1 favors reduction of trans-aliphatic or side-chain C═C bonds, with limited activity toward constrained flavonoid structures. These findings advance our knowledge on the key players of resveratrol metabolism in the gut microbiome.