Enzyme
noun, の adjective
The one element you need to ferment something is an enzyme. That breaks whatever you're trying to ferment down in just the right way.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
今若い女の子の間では、酵素ダイエットが流行っています。
Enzyme diets are popular among young women right now.