Leavened bread is produced with the help of
Yeast
Baker's yeast or Saccharomyces cerevisiae is used to leaven breads or to raise them and give them the airy and fluffy texture. Yeast releases CO2 as a byproduct of aerobic respiration and this gas causes the dough to double in size over time to get it ready for baking. Baking kills off the microbes so we can safely consume the bread.