Structure of microbial communities performing the simultaneous reduction of Fe(II)EDTA.NO2- and Fe(III)EDTA -.
BioDeNOx is a combined physicochemical and biological process for the removal of nitrogen oxides (NOx) from flue gas. In the present study, two anaerobic bioreactors performing BioDeNOx were run consecutively (RUN-1 and RUN-2) at a dilution rate of 0.01 h(-1) with Fe(II)EDTA.NO(2-) and Fe(III)EDTA(-) as electron acceptors and ethanol as electron donor. The measured protein concentration of the reactor biomass of both runs was 120 mg/l. Different molecular methods were used to determine the identity and abundance of the bacterial populations in both bioreactors. Bacillus azotoformans strain KT-1 was recognized as a key player in Fe(II)EDTA.NO(2-) reduction. PCR-denaturing gradient gel electrophoresis analysis of the reactor biomass showed a greater diversity in RUN-2 than in RUN-1. Enrichments of Fe(II)EDTA.NO(2-) and Fe(III)EDTA(-) reducers and activity assays were conducted using the biomass from RUN-2 as an inoculum. The results on substrate turnover, overall microbial diversity, and enrichments and finally activity assays confirmed that ethanol was used as electron donor for Fe(II)EDTA.NO(2-) reduction. In addition, the Fe(III)EDTA(-) reduction rate of the microbial community proved to be feasible enough to run the bioreactors, ruling out the chemical reduction of Fe(III)EDTA(-) with sulfide as was proposed by other researchers.
Kumaraswamy
Rajkumari
R
Department of Biotechnology, Environmental Biotechnology Group, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Kuenen
J Gijs
JG
Kleerebezem
Robbert
R
van Loosdrecht
Mark C M
MC
Muyzer
Gerard
G
D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis; D044822:Biodiversity; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004492:Edetic Acid / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005290:Ferric Compounds / Q000378:metabolism*; D005296:Ferrous Compounds / Q000378:metabolism*; D020459:Genes, rRNA; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D009589:Nitrogen Oxides / Q000378:metabolism*; D009691:Nucleic Acid Denaturation; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005290:Ferric Compounds; D005296:Ferrous Compounds; D009589:Nitrogen Oxides; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; C055526:Fe(II)-EDTA; D000431:Ethanol; D004492:Edetic Acid; C019179:Fe(III)-EDTA