De-ferment is not a widely used word, and neither are its antonyms. However, some possible antonyms for de-ferment could be "ferment," "cultivate," or "provoke." Ferment means to let something undergo a chemical change, while cultivate means to promote growth or development. On the other hand, provoke means to incite or stimulate a reaction. These words are not direct opposites of de-ferment, but can provide some context to its meaning. De-ferment is often used in the context of wine-making or brewing beer, where it refers to the halting of the fermentation process.