Improving biocathode community multifunctionality by polarity inversion for simultaneous bioelectroreduction...

Area of Science:

• Environmental Science
• Microbiology
• Electrochemistry

Background:

• Bioelectrochemical systems (BESs) show promise for wastewater treatment but face challenges with complex wastewater compositions affecting biofilm establishment and stability.
• Enrichment and functional characterization of biocathodes using domestic wastewater (DW) remain under-investigated.

Purpose of the Study:

• To enrich a multifunctional biocathode from a polarity-inverted bioanode established with domestic wastewater.
• To evaluate the biocathode's pollutant removal capabilities using model contaminants as electron acceptors.
• To analyze the microbial community shifts and their correlation with biocathode performance.

Main Methods:

• Enrichment of a biocathode using domestic wastewater in a polarity-inverted bioelectrochemical system.
• Testing biocathode performance with sole and mixed model pollutants (nitrate, nitrobenzene, Acid Orange 7) under open and closed circuit conditions.
• Analysis of microbial community structure and diversity using molecular techniques.

Main Results:

• The enriched biocathode exhibited significantly enhanced reduction of model pollutants compared to anaerobic controls.
• Pollutant removal efficiencies were further improved under closed-circuit conditions for both sole and mixed substrates.
• Significant shifts in the microbial community were observed, with enrichment of fermentative bacteria and versatile pollutant-reducing genera like Pseudomonas, Thauera, and Comamonas.

Conclusions:

• A novel strategy for creating a multifunctional and stable biocathode using domestic wastewater was successfully developed.
• The biocathode's enhanced performance is linked to the maintenance of specific bacterial groups capable of fermentation and versatile pollutant reduction.
• This approach offers a promising avenue for simultaneous bioelectroreduction, potentially integrating with existing wastewater treatment processes.