title: Bacterial communities in a bioelectrochemical denitrification system: the effects of supplemental electron acceptors.
abstract: Electrochemical treatment of nitrate (NO3(-)), nitrite (NO2(-)) and mixtures of nitrate and nitrite was evaluated with microbial catalysts on a cathode in three different bioelectrochemical denitrification systems (BEDS). The removal rates and removal percentage of nitrogen (N) compounds varied during biotic and abiotic operations. The biotic cathode using NO3(-)-N as an electron acceptor showed enhanced removal percentages (88%) compared to the operation with NO2(-)-N (85%). The simultaneous reduction of NO3(-)-N and NO2(-)-N occurred in the operation with a mixture of N compounds. The bacterial diversity from the initial inoculum (return sludge) changed at the end of bioelectrochemical denitrification operation after 55 days. The microbial community composition was different depending on the type of electron acceptor. BEDS operation with NO3(-)-N and NO2(-)-N was enriched with Proteobacteria and Firmicutes respectively. BEDS with a mixture of N electron acceptors showed enrichment with Proteobacteria. There was no clear, distinct microbial community between the cathode biofilm and suspended biomass.
authors.affiliation: Department of Environmental Science and Engineering, Kyung Hee University, Gyeonggi-do, South Korea.
authors.forename: Sanath
authors.initials: S
authors.lastname: Kondaveeti
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea.
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul, South Korea. Electronic address: heedeung@korea.ac.kr.
authors.forename: Hee-Deung
authors.initials: HD
authors.lastname: Park
authors.affiliation: Department of Environmental Science and Engineering, Kyung Hee University, Gyeonggi-do, South Korea. Electronic address: bkmin@khu.ac.kr.
authors.forename: Booki
authors.initials: B
authors.lastname: Min
mesh_terms: D041963:Bacteroidetes / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D019149:Bioreactors; D017931:DNA Primers / Q000235:genetics; D058440:Denitrification / Q000502:physiology*; D055664:Electrochemical Techniques / Q000379:methods*; D004583:Electrons; D064307:Microbiota / Q000502:physiology*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D025341:Principal Component Analysis; D020560:Proteobacteria / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S
keywords: Biocathode; Bioelectrochemical system; Denitrification; Nitrate; Pyrosequencing