In fermented soy sauce, 3-methyl-1-butanol (isoamyl alcohol) is
an important higher alcohol compound with a high impact on
aroma (van der Sluis et al., 2001; Feng et al., 2014). In this study, two
indigenous yeasts showing different abilities to induce sterilizing
effects or enhance flavor production were selected as starters for
salt-reduced soy sauce fermentation. Among the two isolated yeast
strains, T. delbrueckii JBCC-623 with high ethanol productivity was
obtained at the early phase, whereas P. guilliermondii JBCC-848
possessing high 3-methyl-1-butanol productivity was isolated at
the middle stage of spontaneous soy sauce fermentation. In addition,
the JBCC-623 strain showed stronger tolerance to high osmotic
conditions, whereas the JBCC-848 strain possessed various enzyme
activities to metabolize more diverse substrates (Table S1).