Comparative analysis of microbial community between different cathode systems of microbial fuel cells for denitrification.
Two types of cathodic biofilm in microbial fuel cells (MFC) were established for comparison on their performance and microbial communities. Complete autotrophic simultaneous nitrification and denitrification (SND) without organics addition was achieved in nitrifying-MFC (N-MFC) with a total nitrogen (TN) removal rate of 0.35 mg/(L·h), which was even higher than that in denitrifying-MFC (D-MFC) at same TN level. Integrated denaturing gradient gel electrophoresis analysis based on both 16S rRNA and nirK genes showed that Alpha-, Gammaproteobacteria were the main denitrifier communities. Some potential autotrophic denitrifying bacteria which can use electrons and reducing power from cathodes, such as Shewanella oneidensis, Shewanella loihica, Pseudomonas aeruginosa, Starkeya novella and Rhodopseudomonas palustris were identified and selectively enriched on cathode biofilms. Further, relative abundance of denitrifying bacteria characterized by nirK/16S ratios was much higher in biofilm than suspended sludge according to real-time polymerase chain reaction. The highest enrichment efficiency for denitrifiers was obtained in N-MFC cathode biofilms, which confirmed autotrophic denitrifying bacteria enrichment is the key factor for a D-MFC system.
a Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education , Hohai University , Nanjing , People's Republic of China.|b College of Environment , Hohai University , Nanjing , People's Republic of China.|c State Key Engineering Research Center of Efficient Utilization of Water Resources and Engineering Safety , Hohai University , Nanjing , People's Republic of China.
Chao
C
Li
b College of Environment , Hohai University , Nanjing , People's Republic of China.
Ming
M
Xu
b College of Environment , Hohai University , Nanjing , People's Republic of China.
Yi
Y
Lu
a Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education , Hohai University , Nanjing , People's Republic of China.|b College of Environment , Hohai University , Nanjing , People's Republic of China.|c State Key Engineering Research Center of Efficient Utilization of Water Resources and Engineering Safety , Hohai University , Nanjing , People's Republic of China.
Fang
F
Fang
a Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education , Hohai University , Nanjing , People's Republic of China.|b College of Environment , Hohai University , Nanjing , People's Republic of China.|c State Key Engineering Research Center of Efficient Utilization of Water Resources and Engineering Safety , Hohai University , Nanjing , People's Republic of China.
Jiashun
J
Cao
D001419:Bacteria / Q000235:genetics; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D057919:Biological Oxygen Demand Analysis; D058440:Denitrification; D004563:Electrochemistry; D004566:Electrodes / Q000382:microbiology; D005798:Genes, Bacterial; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D012336:RNA, Ribosomal, 16S
Microbial fuel cell; autotrophic denitrifying bacteria; denitrification; microbial community; simultaneous nitrification and denitrification