Anaerobic Nitrate-Dependent Iron (II) Oxidation by a Novel Autotrophic Bacterium,Citrobacter freundii Strain PXL1 |
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| Authors: | Baohua Li Changyan Tian Daoyong Zhang Xiangliang Pan |
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| Affiliation: | 1. Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography , Chinese Academy of Science , Urumqi , China;2. University of Chinese Academy of Sciences , Beijing , China;3. Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography , Chinese Academy of Science , Urumqi , China;4. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang , China |
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| Abstract: | Anaerobic Fe(II) Oxidizing Denitrifiers (AFODN), a type of newly found Fe(II)-oxidizing bacteria, play an important role in iron and nitrogen cycling. In the present study, a novel AFODN strain PXL1 was isolated from anaerobic activated sludge. Phylogenetic analysis of 16S rRNA gene sequence revealed similarity between this strain and Citrobactor freundii. The strain reduced 30% of nitrate and oxidized 85% of Fe(II) over 72 h with an initial Fe(II) concentration of 3.4 mM and nitrate concentration of 9.5 mM. Oxidation of iron was dependent on the reduction of nitrate to nitrite in the absence of other electron donors or acceptors. Nitrate reduction and Fe(II) oxidation followed first-order reaction kinetics. Iron oxides accumulated in the culture were analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The strain recovered deposited oxidized Fe in the form of amorphous Fe oxides. |
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| Keywords: | anaerobic oxidation Fe(II) bio-oxidation nitrate reduction PCR XRD |
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