Which microorganism ferments sugars to make bread rise and is also used in brewing?

Saccharomyces cerevisiae ferments sugars to make bread rise and is also used in brewing.

This single-celled fungus is commonly called baker’s yeast or brewer’s yeast. During fermentation, it converts sugars into ethanol and carbon dioxide. In dough, trapped carbon dioxide expands the mixture; in brewing, ethanol and other fermentation products contribute to the beverage.

Humans have used strains of S. cerevisiae for thousands of years, although the microbiology of fermentation was clarified much later. Louis Pasteur’s nineteenth-century work helped establish that living microorganisms drive alcoholic fermentation rather than the process being purely chemical.

S. cerevisiae is also an important research organism. Scientists use it to study cell division, genetics, aging, and eukaryotic cell biology. Yeast is a fungus, not a bacterium, so calling every fermentation microbe “bacteria” is a common classification error.