Investigation of Microbial Communities of Chinese Sourdoughs Using Culture-Dependent and DGGE Approaches

Sourdough is typically characterized by the complex microbial communities mainly comprising of yeasts and lactic acid bacteria (LAB). The objective of this study was to explore the microbiota of Chinese traditional sourdoughs collected from different areas of China using culture-dependent and denaturing gradient gel electrophoresis (DGGE) methods. A total of 131 yeasts, 2 molds, and 106 LAB strains were isolated and identified. Based on the culture-dependent analysis, the populations of yeasts and LAB were at the level of 10(5) to 10(7) and 10(6) to 10(7) cfu/g, respectively. Similarly, the results of RT-qPCR showed that the values of total yeasts and LAB populations were in the range of 10(6) to 10(7) and 10(7) to 10(8) copies/g, respectively. Using culture-dependent method, a total of 7 yeasts, 2 molds and 7 LAB species were identified. Results showed that Saccharomyces cerevisiae and Lactobacillus plantarum were the predominant species among the yeasts and LAB microflora. Similarly, using PCR-DGGE approach, 7 yeasts, 1 mold and 9 LAB species were detected. The yeast, S. cerevisiae, represented the predominant, while the yeast Candida tropicalis represented the subdominant species of the yeast community. Among the LAB community, Lactobacillus sanfranciscensis was the predominant species, while Lactococcus qarvieae, Enterococcus faecium, Lactobacillus delbrueckii and Enterococcus cecorum were among the less dominant species.

Practical application: In this study, microbiota of Chinese sourdoughs was investigated using culture-dependent and PCR-DGGE methods. It will provide deeper insights into the complex microbial ecosystems of sourdough. On the other hand, it will provide opportunity to utilize the potential of selected strains yeasts and LAB to obtain more desirable fermented food.