fermentation
酵 centers on the process of fermentation, where microorganisms transform organic substances, often producing alcohol or acids.
酵 combines 酉 (a wine vessel, often associated with fermentation) with 孝, which likely contributes the sound. The character originally referred to yeast or leaven used in brewing.
The left side 酉 is a wine jar, and the right side 孝 suggests a child helping an elder. Picture a child adding yeast to a jar to start the fermentation process for making wine.
For コウ, imagine a jar of fermenting koji (こうじ, a mold used in fermentation) bubbling away: koji -> コウ, and the jar 酉 is where the fermentation happens.
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enzyme
fermentation; zymosis
yeast; leaven
DNA repair enzyme
acetone-butanol fermentation
apoenzyme
amino-acid fermentation
alcohol fermentation
killer yeast
protein-digesting enzyme
protease
baker's yeast (Saccharomyces cerevisiae); brewer's yeast
brewer's yeast; brewery yeast
flavin enzyme; flavoenzyme
flavoenzyme
methane fermentation
monoamine oxidase; MAO
monoamine oxidase inhibitor; MAO inhibitor; MAOI
bottom fermentation (brewing)
multiple parallel fermentation (esp. in sake brewing)