Stochastic process dominated community assembly during high-temperature Daqu storage, leading to reduced microbial...

Area of Science:

• Microbiology
• Metabolomics
• Food Science

Background:

• High-temperature Daqu (HTD) is crucial for fermented foods, but its maturation mechanisms are unclear.
• Understanding microbial and metabolic changes during HTD storage is key for quality control.

Purpose of the Study:

• To investigate the ecological mechanisms driving HTD maturation during storage.
• To identify microbial and metabolic shifts and their relationship with environmental factors.

Main Methods:

• Integrated high-throughput 16S rRNA and ITS amplicon sequencing.
• Metabolomic profiling of volatile and non-volatile compounds.
• Neutral community and null model analyses, structural equation modeling.

Main Results:

• Storage selectively enriched stress-tolerant microbes (e.g., Kroppenstedtia, Thermoascus) and altered metabolic profiles (increased alcohols, pyrazines; decreased esters).
• Microbial community assembly was dominated by stochastic processes influenced by environmental heterogeneity.
• Reduced microbial network complexity and stability were observed, with distinct bacterial and fungal roles in flavor compound synthesis.

Conclusions:

• HTD storage acts as an ecosystem governed by stochastic assembly, impacting microbial community structure and function.
• Physicochemical factors influence fungal diversity, while storage affects microbial composition.
• The study provides a framework for quality control by managing key microbial functional modules in HTD.