Impact of anodophilic biofilm bioelectroactivity on the denitrification behavior of air-cathode microbial fuel cells

Wenjuan Zhao; YiZhao Gao; Yongli Zhao; Xiaoya Deng; Jun Shao; Shuiliang Chen

doi:10.1002/bit.27972

Impact of anodophilic biofilm bioelectroactivity on the denitrification behavior of air-cathode microbial fuel cells

Biotechnol Bioeng. 2022 Jan;119(1):268-276. doi: 10.1002/bit.27972. Epub 2021 Nov 3.

Authors

Wenjuan Zhao¹, YiZhao Gao¹, Yongli Zhao¹, Xiaoya Deng¹, Jun Shao^{1

2}, Shuiliang Chen^{1

2}

Affiliations

¹ Department of Chemistry and Chemical Engineering and Nanofiber Engineering Center of Jiangxi Province, Jiangxi Normal University, Nanchang, China.
² Key Laboratory of Functional Small Molecules for Ministry of Education, Jiangxi Normal University, Nanchang, China.

PMID: 34698369
DOI: 10.1002/bit.27972

Abstract

Generally, high bioelectroactivity of anodophilic biofilm favors high power generation of microbial fuel cell (MFC); however, it is not clear whether it can promote denitrification of MFC synchronously. In this study, we studied the impact of anodophilic biofilm bioelectroactivity on the denitrification behavior of air-cathode MFC (AC-MFC) in steady state and found that high bioelectroactivity of anodophilic biofilm not only favored high power generation of the AC-MFC, but also promoted the growth of denitrifers at the anodes and strengthened denitrification. Anodophilic biofilms of AC-MFC with various bioelectroactivity were acclimated at conditions of open circuit (OC), R_ext of 1000 Ω and 20 Ω (denoted as AC-MFC-OC, AC-MFC-1000Ω, and AC-MFC-20Ω, respectively) and performed for over 100 days. Electrochemical tests and microbial analysis results showed that the anode of the AC-MFC-20Ω delivered higher current response of both oxidation and denitrification and had higher abundance of electroactive bacteria than the AC-MFC-OC, AC-MFC-1000Ω, demonstrating a higher bioelectroactivity of the anodophilic biofilms. Moreover, these electroactive bacteria favored the accumulation of denitrifers, like Thauera and Alicycliphilus, probably by consuming trace oxygen through catalyzing oxygen reduction. The AC-MFC-20Ω not only delivered a 61.7% higher power than the AC-MFC-1000Ω, but also achieved a stable and high denitrification rate constant (k_DN ) of 1.9 h^-1 , which was 50% and 40% higher than that of the AC-MFC-OC and AC-MFC-1000Ω, respectively. It could be concluded that the high bioelectroactivity of the anodophilic biofilms not only favored high power generation of the AC-MFC, but also promoted the enrichment of denitrifers at the anodes and strengthened denitrification. This study provided an effective method for enhancing power generation and denitrification performance of the AC-MFC synchronously.

Keywords: anodophilic biofilms; bioelectroactivity; denitrification; single-chamber air-cathode microbial fuel cell; steady state.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air
Bioelectric Energy Sources / microbiology*
Biofilms*
Denitrification / physiology*
Electrodes / microbiology