Microbial consortium and its spatial distribution in a compartmentalized anaerobic reactor

Area of Science:

• Environmental microbiology
• Biotechnology
• Anaerobic digestion

Background:

• Compartmentalized anaerobic reactors (CARs) offer high-rate treatment potential.
• Understanding microbial consortia and their spatial distribution is crucial for optimizing CAR performance.

Purpose of the Study:

• To investigate the microbial consortium, spatial distribution, and their relationship with the performance of a novel CAR.
• To elucidate the roles of different microbial groups within the CAR's compartments.

Main Methods:

• Polymerase chain reaction (PCR)
• Denaturing gradient gel electrophoresis (DGGE)
• Fluorescence in situ hybridization (FISH)

Main Results:

• Predominant archaea included Methanobacterium, Methanosaeta, and Methanospirillum. Key bacteria belonged to Firmicutes, Deltaproteobacteria, Spirochaetes, Actinobacteria, and Gammaproteobacteria.
• Methanogenic archaea (MA), hydrogen-producing acetogenic bacteria (HAB), and hydrolytic fermentative bacteria (HFB) dominated the upper, middle, and bottom compartments, respectively.
• Granular sludge exhibited a stratified microbial structure (HFB in outer shell, HAB in middle layer, MA in core) with varying homogeneity across compartments.

Conclusions:

• The spatial distribution of microbial populations within the CAR is stratified and influenced by organic loading rate and chemical composition.
• This stratified structure is key to the reactor's high-rate performance.
• The findings provide insights into microbial ecology within CARs for improved wastewater treatment.