Saccharomyces cerevisiae is used for industrial bread leavening.
Nowadays complex starter cultures (sourdough), containing yeasts and lactic acid bacteria (Sacch. cerevisiae, Candida krusei, Hansenula anomala, Lactobacillus sanfranciscensis, Lb. brevis, Lb. fermentum, Lb. pontis, Lb. panis, Lb. mindensis, Lb. plantarum) are used in traditional bread-making; based on the technology used for production, sourdoughs can be grouped into three types: type I, type II and type III. Type I sourdoughs are produced through traditional techniques and are refreshed every day to maintain active the endogenous microflora; type II sourdoughs, used as dough-souring supplements during bread preparation, are semi-fluid preparations characterized by long fermentation periods (from 2 up to 5 days) and fermentation temperature sometimes >30°C. Finally, type III sourdoughs are dried preparations containing LAB resistant to the drying process.