Diversity of Ferrous Iron-Oxidizing, Nitrate-Reducing Bacteria and their Involvement in Oxygen-Independent Iron Cycling
| Autor: | Kristina Lotte Straub, Bernhard Schink, Wilhelm Schönhuber, Berit E. E. Buchholz-Cleven |
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| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
anaerobic cycling of iron
Geobacter bremensis biology Acidovorax nitrate-reducing bacteria biology.organism_classification Microbiology Ferrous Aquabacterium chemistry.chemical_compound Denitrifying bacteria ferrous iron-oxidizing Nitrate chemistry ddc:570 Earth and Planetary Sciences (miscellaneous) Environmental Chemistry Proteobacteria Bacteria General Environmental Science |
| Zdroj: | Geomicrobiology Journal |
| Popis: | In previous studies, three different strains (BrG1, BrG2, and BrG3) of ferrous iron-oxidizing, nitrate-reducing bacteria were obtained from freshwater sediments. All three strains were facultative anaerobes and utilized a variety of organic substrates and molecular hydrogen with nitrate as electron acceptor. In this study, analyses of 16S rDNA sequences showed that strain BrG1 was affiliated with the genus Acidovorax, strain BrG2 with the genus Aquabacterium, and strain BrG3 with the genus Thermomonas. Previously, bacteria similar to these three strains were detected with molecular techniques in MPN dilution series for ferrous iron-oxidizing, nitrate-reducing bacteria inoculated with different freshwater sediment samples. In the present study, further molecular analyses of these MPN cultures indicated that the ability to oxidize ferrous iron with nitrate is widespread amongst the Proteobacteria and may also be found among the Gram-positive bacteria with high GC content of DNA. Nitrate-reducing bacteria oxidized ferrous iron to poorly crystallized ferrihydrite that was suitable as an electron acceptor for ferric iron-reducing bacteria. Biologically produced ferrihydrite and synthetically produced ferrihydrite were both well suited as electron acceptors in MPN dilution cultures. Repeated anaerobic cycling of iron was shown in a coculture of ferrous iron-oxidizing bacteria and the ferric iron-reducing bacterium Geobacter bremensis. The results indicate that iron can be cycled between its oxidation states +II and +III by microbial activities in anoxic sediments. |
| Databáze: | OpenAIRE |
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