Saccharomyces cerevisiae yeast. Digital illustration showing budding yeast cells, pseudohyphae, asci and ascospores. Known as baker's or brewer's yeast, this fungus consists of single vegetative cells. The larger 'mother' cells are budding off smaller daughter cells after cell division. Saccharomyces cerevisiae is able to ferment sugar, producing alcohol and carbon dioxide in the process. It has long been used in the brewing of beer, production of wine, and in baking leavened bread (causing the dough to rise). Also, it is used as a probiotic in the treatment of diarrheal infections.