Amylase
Japanese: アミラーゼ（デンプン分解酵素）
An enzyme that breaks starch into sugars like glucose and maltose. Secreted by koji mold, it is the key agent of saccharification.
Amylase is an enzyme that cuts starch chains into sugars. Human saliva contains it, but in fermentation, the amylase secreted by koji mold takes center stage.
Two main types exist: α-amylase, which randomly cleaves starch chains, and β-amylase, which trims maltose (a disaccharide) from the ends. Together, they efficiently convert starch to glucose.
Amazake is sweet without sugar because amylase has converted rice starch into glucose. In sake brewing, this saccharification proceeds simultaneously with alcoholic fermentation in the same tank—multiple parallel fermentation. Without amylase, brewing from grains would be impossible.