Acclimation of 2-chlorophenol-biodegrading activated sludge and microbial community analysis

Area of Science:

• Environmental Microbiology
• Biotechnology
• Wastewater Treatment

Background:

• 2-chlorophenol is a persistent pollutant in industrial wastewater.
• Activated sludge requires acclimation for effective biodegradation of recalcitrant compounds.
• Microbial community structure influences biodegradation efficiency.

Purpose of the Study:

• To domesticate activated sludge for high-concentration 2-chlorophenol biodegradation.
• To investigate microbial community shifts during acclimation.
• To identify key bacterial players and their roles in 2-chlorophenol degradation.

Main Methods:

• Stepwise increase of 2-chlorophenol concentration in sequencing batch reactors.
• High-throughput sequencing for microbial community analysis.
• Monitoring of 2-chlorophenol degradation and bacterial abundance.

Main Results:

• Successfully domesticated activated sludge capable of degrading 40 mg/L 2-chlorophenol using glucose as cosubstrate.
• Microbial richness and diversity initially increased then decreased with rising 2-chlorophenol levels.
• Saccharibacteria_norank, Bacillus, Saprospiraceae_uncultured, and Lactococcus were dominant; Bacillus and Pseudomonas were key degraders.
• Bacterial tolerance and degradation capability were not directly correlated, indicating synergistic effects.

Conclusions:

• Activated sludge can be effectively acclimated to degrade high concentrations of 2-chlorophenol.
• Microbial community structure is dynamic and impacts biodegradation efficiency.
• 2-chlorophenol degradation likely involves synergistic interactions among diverse bacterial species, not solely known degraders.