Effects of food-derived Staphylococcus equorum, Staphylococcus succinus and Staphylococcus xylosus on volatile compounds production during soybean fermentation.

To investigate differences in volatile compound production among Staphylococcus species during soybean fermentation, Staphylococcus equorum, S. succinus, and S. xylosus isolated from fermented food were inoculated as starter cultures. Soybeans without starter cultures were used as a control group. Three Staphylococcus species collectively produced 15 additional volatile compounds compared to the control group, with 10 compounds being common to all species and 5 being species-specific. Through genomic analysis, it was confirmed that all three Staphylococcus species possessed genes necessary to produce these commonly detected volatile compounds. However, only three out of five species-specific volatile aroma compounds had identifiable production pathways. While (3-methylphenyl)methanol and 3-hydroxybutan-2-one were detected only in S. equorum, all three Staphylococcus species possessed genes required for their production, contradicting the detection of volatile compounds. In contrast, octan-2-one showed alignment between genes required for its production and its actual detection as a volatile compound. In conclusion, this study confirmed that all three Staphylococcus species could influence the production of volatile compounds during soybean fermentation, although their inter-species differences were not significant. This was supported by genomic results.