Enhanced nitrogen removal by Comamonas 110 colonization and bioaugmentation in sequencing batch activated sludge...

Area of Science:

• Environmental microbiology
• Wastewater treatment
• Bioaugmentation strategies

Background:

• Pure functional microbial strains show high pollutant removal but struggle with environmental persistence.
• Activated sludge systems require efficient and stable microbial communities for effective wastewater treatment.
• Bioaugmentation with specialized strains like Comamonas 110 is a potential strategy to enhance treatment performance.

Purpose of the Study:

• To optimize inoculation strategies for Comamonas 110 in activated sludge systems.
• To evaluate the impact of Comamonas 110 on nitrogen removal efficiency and microbial community stability.
• To elucidate the underlying mechanisms of Comamonas 110 colonization and its interaction with the native microbiome.

Main Methods:

• Optimization of Comamonas 110 initial dosage and operational parameters in activated sludge.
• 16S rRNA gene sequencing for analyzing microbial community structure and abundance.
• Monod modeling to understand microbial kinetics.
• Metagenomic analysis to investigate functional gene expression related to nitrogen metabolism and cell adhesion.

Main Results:

• A 30% initial dosage of Comamonas 110, combined with operational adjustments, led to stable colonization (15.22% abundance at day 180).
• Enhanced nitrogen removal efficiency reached 44% by day 180 in inoculated systems.
• Comamonas 110 modulated the microbial community by suppressing Nitrite-Oxidizing Bacteria (NOB) and promoting Ammonia-Oxidizing Bacteria (AOB).
• Significant increases in denitrifying enzymes (NAR and NIR) and upregulated TCA cycle and nitrogen metabolism genes were observed.
• Activation of Extracellular Polymeric Substance (EPS) synthesis genes facilitated co-aggregation with native microbes.

Conclusions:

• Optimized inoculation strategies and operational parameter regulation can ensure the stable colonization and efficacy of bioaugmentation strains like Comamonas 110.
• Comamonas 110 enhances nitrogen removal through direct microbial activity and by modulating the native microbiome, including AOB/NOB balance and denitrification pathways.
• The study highlights the importance of microbiome-environment interactions in successful bioaugmentation for wastewater treatment.