Which microorganism is used to make bread soft and fluffy how this happens?

Yeast, specifically Saccharomyces cerevisiae, is the microorganism used to make bread soft and fluffy. During the fermentation process, yeast consumes sugars in the dough and produces carbon dioxide gas and alcohol. The carbon dioxide gas gets trapped in the dough's gluten structure, causing it to rise and create a light, airy texture. This process not only contributes to the bread's softness but also enhances its flavor.