fermentation

1. Any of many anaerobic biochemical reactions in which an enzyme (or several enzymes produced by a microorganism) catalyses the conversion of one substance into another; especially the conversion (using yeast) of sugars to alcohol or acetic acid with the evolution of carbon dioxide (countable, uncountable)
2. A state of agitation or excitement; a ferment. (countable, uncountable)

الجمع fermentations