NCERT · Class 12 · Biology · Microbes in Human WelfareThe yeast Saccharomyces cerevisiae, commonly referred to as brewer's yeast, is of immense commercial importance and has been used for centuries in food processing, specifically in baking and brewing industries. In the baking industry, yeast is added to dough for making bread and other bakery products. During this process, yeast ferments the sugars present in the dough through anaerobic respiration, producing carbon dioxide gas and ethanol. The trapped carbon dioxide bubbles expand and cause the dough to rise, which gives bread its characteristic soft, spongy, and porous texture after baking. In the brewing industry, the same yeast is utilized for fermenting malted cereals and fruit juices to produce various alcoholic beverages such as beer, wine, whisky, brandy, and rum. Depending upon the type of raw material used for fermentation and the type of processing (with or without distillation), different alcoholic drinks are produced on a large commercial scale.