Temperature adaptability drives functional diversity and horizontal gene transfer within microbial communities in...

Area of Science:

• Microbiology
• Fermentation Science
• Food Science

Background:

• High-temperature Daqu (HTD) solid-state fermentation is crucial for efficient fermentation but its temperature-dependent microbial dynamics remain unclear.
• Understanding microbial assembly, domestication, and metabolic profiles under varying temperatures is essential for optimizing HTD production.

Purpose of the Study:

• To investigate the impact of temperature adaptability on microbial communities, flavor profiles, and metabolic networks in three distinct HTDs.
• To analyze horizontal gene transfer (HGT) events and their association with temperature adaptation and flavor metabolism in HTD.

Main Methods:

• Analysis of volatile compounds, microbial community structure (bacteria and fungi), metabolic networks, and HGT events using MetaCHIP.
• Comparative analysis of three HTDs (Renshu, Jiushang, Maoyuan) to identify correlations between microbial traits, flavor, and sample proximity.

Main Results:

• Identified 125 volatile compounds, with specific pyrazines, acids, and alcohols as key flavor substances.
• Revealed shared dominant bacterial genera (Bacillus, Kroppenstedtia) and fungal genera (Paecilomyces, Aspergillus, Rasamsonia, Lichtheimia).
• Demonstrated strong correlations between flavor metabolism, microbial structure, and HGT events with sample phylogenetic distance, with HGT linked to high-temperature adaptability and characteristic flavor.

Conclusions:

• Temperature stress significantly shapes microbial regulation and adaptive gene transfer in stacked fermented HTDs.
• Microbial structural and functional traits converge with decreasing sample proximity, indicating localized adaptation.
• Findings offer critical insights for HTD quality classification and optimizing solid-state fermentation efficiency through microbial domestication.