Deciphering Succession and Assembly Patterns of Microbial Communities in a Two-Stage Solid-State Fermentation System

Area of Science:

• Microbiology
• Food Science
• Ecology

Background:

• Microbiota play crucial roles in natural and industrial settings, yet their community formation and succession patterns, especially after disturbances, remain poorly understood.
• The Xiaoqu liquor brewing process, involving aerobic saccharification and anaerobic fermentation, offers a tractable model to study multistage microbial community succession.

Purpose of the Study:

• To explore multistage microbial community succession patterns in the Xiaoqu liquor brewing process.
• To analyze the influence of different starters (pure vs. traditional) on microbial composition, physicochemical factors, and metabolite profiles.
• To understand the ecological processes and determinants driving microbial community dynamics and their impact on flavor metabolism.

Main Methods:

• Comparative analysis of microbial communities (bacteria and fungi) in brewing grains using two distinct starter types.
• Monitoring of physicochemical factors and metabolite composition throughout the two-stage brewing process (saccharification and fermentation).
• Investigating the origins of saccharification and fermentation microbiota and the ecological processes (species replacement, loss) shaping community succession.

Main Results:

• Both pure and traditional starter groups exhibited similar microbial succession patterns, with environmental microbes (Lactobacillaceae, Saccharomyces) dominating fermentation.
• Bacterial community succession was driven by species replacement, while fungal succession involved both replacement and loss.
• Grain acidification and hypoxia were identified as key determinants for bacterial and fungal community succession, respectively.
• Despite different starters, similar fermentation microbiota led to comparable metabolite profiles, though starter-specific microbes influenced alcohol, acid, and ester production.

Conclusions:

• The Xiaoqu liquor brewing system serves as a valuable model for studying multistage microbial community succession.
• Microbial community dynamics in liquor brewing are influenced by starter origins, ecological processes, and environmental factors like acidification and hypoxia.
• Understanding these succession patterns and their impact on metabolite synthesis provides a basis for optimizing fermented food production and regulating microbial ecosystems.