Co-occurrence network analysis reveals thermodynamics-driven microbial interactions in methanogenic bioreactors

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Methanogenic bioreactors are utilized for treating complex aromatic compounds in purified terephthalic acid (PTA) wastewater.
• Understanding microbial interactions is key to optimizing bioreactor efficiency.

Purpose of the Study:

• To characterize microbial population interactions in PTA-degrading methanogenic bioreactors.
• To identify dominant microbial populations and their roles in aromatic compound degradation.

Main Methods:

• Analysis of 42 samples from 10 PTA-degrading methanogenic bioreactors.
• Identification of dominant microbial populations using 16S rRNA gene iTag sequencing.
• Co-occurrence network analysis to understand microbial community structure and interactions.

Main Results:

• Identified 54 dominant populations, including methanogens, syntrophs, and unknown clades, comprising 73.9% of sequences.
• Revealed two distinct co-occurrence networks: one centered on aromatic compound degraders (Group AR) and another on fatty acid degraders (Group FA).
• Group AR syntrophs showed no direct correlation with hydrogenotrophic methanogens, unlike Group FA syntrophs, suggesting differential interactions and potential roles of uncultivated taxa.

Conclusions:

• Microbial communities in PTA bioreactors form complex interaction networks involving syntrophs and methanogens.
• Uncultivated taxa play a significant role in mediating syntroph-methanogen interactions and supporting aromatic compound degradation.
• These findings highlight the metabolic orchestration of diverse microbial niches for effective wastewater treatment.