No, yeast extract is not a suitable substitute for dry yeast in baking or fermentation processes. Yeast extract is a concentrated form of the compounds found in yeast, such as proteins, amino acids, and flavor compounds. It is commonly used as a flavoring agent or nutrient supplement in savory dishes, soups, and sauces.
Dry yeast, on the other hand, is an active form of yeast that contains living microorganisms capable of fermenting sugars and producing carbon dioxide gas, which causes dough to rise. This is essential for the leavening process in baking. Dry yeast needs to be rehydrated in warm water or added directly to the dough mixture to activate and begin the fermentation process.
If a recipe calls for dry yeast, it is important to use the appropriate type of yeast to achieve the desired results. Yeast extract cannot replace the leavening properties of active dry yeast, so it's not a suitable substitute in baking or fermentation recipes.