Bacterial diversity in traditional sourdough from different regions in China

Sourdough is widely used for the preparation of traditional sourdough breads in Europe and as an important inoculum for steamed buns prepared in Asian countries, especially China. This study aims to characterize Chinese traditional sourdoughs in terms of their taxonomic compositions, physicochemical characteristics, bacterial diversity and functional features. Thirty geographically diverse sourdoughs were collected from three regions across China. High-throughput sequencing and bioinformatics were used to characterize the bacterial diversity of the sourdoughs from the different sampling sites. The results showed that the West group was significantly different from the North and South groups in the dominant genera (mainly Lactobacillus, Pediococcus and Leuconostoc) and metabolic pathways (metabolism of terpenoids and polyketides, MTP, and xenobiotics biodegradation and metabolism, XBM), whereas samples from the North and South groups were not significantly different from each other. This is the first report of the genus Clostridium in sourdough and the first report of metabolic pathways related to MTP and XBM in sourdough. This research provides a thorough description and analysis of the relationship between bacterial diversity and geographic region in sourdough.