Microbiological and Biomolecular Methods Applicable to the Isolation, Characterization and Identification of Microbial Sourdough Strains

The use of sourdough in high-quality fermentation processes is characterized by a microbiome composed of bacteria and yeasts cohabiting in a certain harmony level. In general, bacteria acidify the dough, produce volatile compounds, and develop flavor, and yeasts, which are adapted to this environment, hydrolyze carbohydrates and synthesize antioxidants, enzymes, and antimicrobials. Moreover, yeasts also produce gases due to their high fermentative activity, expanding the dough. However, to understand the mechanisms involved in these interactions, it is of fundamental importance to understand the real composition of this microbiome. Thus, the classic microbiological methods used to isolate and characterize sourdough strains are still indispensable to select cultivable strains of technological interest. On the other hand, biomolecular methods have increased the ability to explore this microbiome by using both culture-dependent and culture-independent techniques with different resolutions. In this chapter, some methods currently used to isolate, characterize and identify bacteria and yeasts present in sourdough will be explored and contextualized in practical applications of interest for sourdough-based products.