A Human Oral Bacterial β-Glucosidase Involved in Aroma Release from Glycosides

Flavor perception is driven by the interplay of gustation, olfaction, and somatosensory inputs. Among the factors influencing flavor perception, the enzymatic activity of oral bacterial glycosidases plays a role in modulating taste and aroma, generating aroma molecules from glycosidic precursors. This study investigates the in vitro capacity of oral bacterial β-glucosidases to hydrolyze glycosidic aroma precursors. Seven candidate enzymes from oral bacteria were recombinantly produced and screened for glycosidase activity. Among them, only the β-glucosidase from Prevotella sp. (PsBG1) showed hydrolytic activity toward chromogenic substrates and the aroma glucosides tested, leading to the release of salicylaldehyde, hexanol, and octanol, as confirmed by GC-MS. Structural analysis of PsBG1 revealed key residues involved in substrate recognition and catalysis. These results identify a specific oral bacterial enzyme capable of releasing aroma-active compounds from glycosides in vitro, suggesting a potential contribution of oral microbiota enzymatic activity to in-mouth aroma release.