Halotolerant yeast
Japanese: 耐塩性酵母
Yeasts capable of growing in high-salt environments. Active in miso and soy sauce mash, they produce distinctive aromatic compounds.
The mash of miso and soy sauce is a harsh environment with salt concentrations of 10–18%. Most microorganisms cannot survive such salinity, yet halotolerant yeasts thrive there without difficulty.
Zygosaccharomyces rouxii is the representative species. Under high osmotic pressure, it generates aromatic compounds such as esters and alcohols, lending miso and soy sauce their complex fragrances.
Halotolerant yeasts become active from the middle to later stages of fermentation. After lactic acid bacteria set the acidity, yeast creates the aroma. This relay is what produces the profound flavors of fermented foods. An important concept bridging theory and practice. One of the important elements supporting fermentation's diversity.