Expression of key hydrolases for soy sauce fermentation in Zygosaccharomyces rouxii.

Several key hydrolases in soy sauce fermentation such as proteases, peptidases, and glutaminases are supplied by Aspergillus sojae or Aspergillus oryzae. The genes encoding these hydrolases were successfully expressed in salt-tolerant yeast Zygosaccharomyces rouxii. These transformants are expected to supply extra hydrolases during soy sauce fermentation process.