Structure and metabolic function of spatiotemporal pit mud microbiome.

Area of Science:

• Microbiology
• Environmental Science
• Biotechnology

Background:

• Pit mud (PM) harbors unique microbial ecosystems crucial for Baijiu production.
• PM microbes exhibit tolerance to ethanol and acids, forming a distinct environment.
• Limited understanding of PM microbial ecology and metabolic functions, especially novel lineages.

Purpose of the Study:

• To comprehensively analyze microbial community structure and metabolic functions in spatiotemporal PM samples.
• To investigate the phylogeny, horizontal gene transfer (HGT), and interactions with carboxyl compounds in PM.
• To elucidate the ecological dynamics and evolutionary pathways within the PM ecosystem.

Main Methods:

• Metagenomic analysis to profile microbial communities.
• Chemical derivatization liquid chromatography-mass spectrometry (LC-MS) for metabolite analysis.
• Construction of metagenome-assembled genomes (MAGs) and phylogenetic analysis.

Main Results:

• Prokaryotic communities in PM exhibit three spatiotemporal stages: initial (Lactobacillus-dominated), transitional, and equilibrium.
• Identified 178 high-quality MAGs involved in carbon, nitrogen, and sulfur cycles, with Wood-Ljungdahl and rTCA pathways for carbon fixation.
• Widespread HGT observed, significantly impacting fermentation, carbon fixation, methane production, and nutrient cycling.

Conclusions:

• PM microbial communities evolve through distinct developmental stages, influenced by environmental factors and HGT.
• Lactobacillus, methanogens, and Clostridium dynamics are key indicators of PM quality for Baijiu production.
• Understanding spatiotemporal PM ecology and microbial interactions provides insights into fermentation processes and quality assessment.