Both Zygosaccharomyces rouxii (S) and Torulopsis versatilis (T) are salt-resist yeasts and have been
widely used in high-salt liquid fermentation of soy sauce during which the salt concentration is about 17%.
because S and T could grow in media with 18% salt, while their mutant strains S3-2 and T3-5, which were
obtained by genome rearrangement technology were even able to grow in 21% 22% salt. Yeast strains play
an important role in soy-sauce brewing. For example, Z. rouxii (S) could increase the content of HEMF which
is an important flavor compounds in soy sauce. While T. versatilis (T) could take good advantage of the
reducing sugars in the moromi to produce polyalcohols, 4-EG and 4-EP and the right amount of 4-EG and 4-
EP can make soy sauce have a rich aroma of esters and increase its mellow taste.