What process do microorganisms, primarily yeast, use to produce carbon dioxide for brewing and baking?

The process used by microorganisms, particularly yeast, to produce carbon dioxide for brewing and baking is fermentation. During fermentation, yeast converts sugars into alcohol and carbon dioxide in anaerobic conditions, meaning it occurs without the presence of oxygen. This process is crucial in both brewing and baking, as the carbon dioxide produced creates bubbles that help dough rise and gives beer its carbonation.

While aerobic respiration involves the use of oxygen to produce energy and can also lead to carbon dioxide production, it is not the main process used in brewing and baking, where the environment is typically anaerobic to promote fermentation. Photosynthesis, on the other hand, is the process where plants, algae, and some bacteria convert light energy into chemical energy, which does not apply in this context as it does not involve yeast or the production of beer or bread. Thus, fermentation is the specific process at play here, emphasizing its importance in food and beverage production.