Yeast is a saprophytic fungus. Saccharomyces cerevisiae is found in sugary rich substances like rotten fruits, rotten juice and other organic substances containing sugar. It is commonly known as baker's yeast and brewer's yeast because in the baking industry it is used to make the bread soft and porous and it is used in the brewing industry for the preparation of ethyl alcohol.
It is the incomplete breakdown of glucose into ethyl alcohol and carbon dioxide in an anaerobic condition in the presence of enzymes invertase and zymase.
C6H12O6 → 2 C2H5OH + 2 CO + heat energy
Saccharomyces cerevisiae is a unicellular eukaryotic fungus. The cell structure is round or oval in shape. The cell wall is made up of chitin. It contains all double membrane-bound cell organelles like ER, Golgi body, mitochondria, ribosomes etc. There is the presence of centrally located large vacuole covered by tonoplast. Reserved food material is glycogen, volutin granule, and oil droplets.