Microbial ecology dynamics during rye and wheat sourdough preparation

Area of Science:

• Microbiology
• Food Science
• Bacteriology

Background:

• Sourdough fermentation relies on a complex microbial community.
• Understanding the dynamics of bacterial and yeast populations is crucial for consistent sourdough production.

Purpose of the Study:

• To characterize the bacterial ecology during rye and wheat sourdough preparation.
• To investigate the succession of microbial communities during sourdough fermentation.

Main Methods:

• 16S rRNA gene pyrosequencing was used to analyze bacterial diversity.
• Viable plate counts, acidification rates, and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) were employed.
• Biochemical and microbial features were analyzed using permutation analysis.

Main Results:

• Initial flour contaminants (Proteobacteria, Bacteroidetes) were rapidly inhibited, with Enterobacteriaceae persisting.
• Firmicutes, primarily lactic acid bacteria, became dominant within one day.
• A succession of lactic acid bacteria species (Weissella, Lactobacillus sakei group, Leuconostoc, Lactococcus lactis) was observed in wheat sourdough.
• Saccharomyces cerevisiae dominated yeast populations throughout propagation.

Conclusions:

• Sourdough microbial ecology undergoes significant evolution during preparation.
• Lactic acid bacteria rapidly establish dominance, shaping the sourdough environment.
• Bacterial and yeast dynamics are key to successful sourdough fermentation.