There are 250 or so of these yeast species that can convert sugar into carbon dioxide and alcohol – valuable skills that humans have used for millennia. Among these 24 species is one called Saccharomyces cerevisiae, which means “sugar-eating fungus.” This is bread yeast, the yeast we humans know and love most dearly for the food and drinks it helps us make. Poh Kim Yeoh/EyeEm via Getty Images via The ConversationNo yeast, no breadWhen you mix yeast with a bit of water and flour, the yeast begins to eat the long chains of carbohydrates found in the flour called starches. Yeast is everywhere, and it’s really easy to collect yeast at home that you can use for baking. Today, scientists use yeast in drug discovery and as tools to study cell growth in mammals and are exploring ways to use yeast to make biofuel from waste products like cornstalks.