What is produced by bacteria during fermentation besides alcohol?

During fermentation, bacteria not only produce alcohol but also generate gases and acids. One of the primary byproducts of fermentation is carbon dioxide. This gas is produced when certain bacteria convert sugars into energy without oxygen, a process that occurs in various forms of fermentation, including alcoholic fermentation and lactic acid fermentation.

In the context of alcoholic fermentation, yeast (a type of fungus) converts sugars into ethanol (alcohol) and carbon dioxide. Bacteria involved in lactic acid fermentation also produce carbon dioxide under certain conditions, though their primary byproduct is typically lactic acid. The presence of carbon dioxide is significant, as it can cause bread to rise and is responsible for the bubbles in carbonated beverages.

Other substances like acetic acid and lactic acid are also produced during fermentation but are specific to certain types of fermentation processes. For instance, acetic acid is associated with the fermentation of ethanol by acetic acid bacteria, and lactic acid is produced primarily by lactic acid bacteria. However, carbon dioxide is more universally recognized as a common byproduct of fermentation processes involving a wide range of bacteria and yeasts.