Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain
Nitrate-reducing iron(II) oxidation (NRFO) has been intensively reported in various bacteria. Iron(II) oxidation is found to be involved in both enzymatic and chemical reactions in nitrate-reducing Fe(II)-oxidizing microorganisms (NRFOMs). However, little is known about the relative contribution of...
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MDPI AG
2022-08-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/17/5581 |
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| author | Ming-Jun Li Meng-Yun Wei Xiao-Ting Fan Guo-Wei Zhou |
| author_facet | Ming-Jun Li Meng-Yun Wei Xiao-Ting Fan Guo-Wei Zhou |
| author_sort | Ming-Jun Li |
| collection | DOAJ |
| description | Nitrate-reducing iron(II) oxidation (NRFO) has been intensively reported in various bacteria. Iron(II) oxidation is found to be involved in both enzymatic and chemical reactions in nitrate-reducing Fe(II)-oxidizing microorganisms (NRFOMs). However, little is known about the relative contribution of biotic and abiotic reactions to iron(II) oxidation for the common nitrate reducers during the NRFO process. In this study, the typical nitrate reducers, four <i>Enterobacter</i> strains <i>E. hormaechei</i>, <i>E. tabaci</i>, <i>E. mori</i> and <i>E. asburiae</i>, were utilized as the model microorganisms. The comparison of the kinetics of nitrate, iron(II) and nitrite and N<sub>2</sub>O production in setups with and without iron(II) indicates a mixture of enzymatic and abiotic oxidation of iron(II) in all four <i>Enterobacter</i> strains. It was estimated that 22−29% of total oxidized iron(II) was coupled to microbial nitrate reduction by <i>E. hormaechei</i>, <i>E. tabaci</i>, <i>E. mori</i>, and <i>E. asburiae</i>. <i>Enterobacter</i> strains displayed an metabolic inactivity with heavy iron(III) encrustation on the cell surface in the NRFOmedium during days of incubation. Moreover, both respiratory and periplasmic nitrate-reducing genes are encoded by genomes of <i>Enterobacter</i> strains, suggesting that cell encrustation may occur with periplasmic iron(III) oxide precipitation as well as the surface iron(II) mineral coating for nitrate reducers. Overall, this study clarified the potential role of nitrate reducers in the biochemical cycling of iron under anoxic conditions, in turn, re-shaping their activity during denitrification because of cell encrustation with iron(III) minerals. |
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| language | English |
| last_indexed | 2024-03-10T01:29:36Z |
| publishDate | 2022-08-01 |
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| series | Molecules |
| spelling | doaj.art-560f89ba63a44f2a969e77ff0c73da6c2023-11-23T13:44:31ZengMDPI AGMolecules1420-30492022-08-012717558110.3390/molecules27175581Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> StrainMing-Jun Li0Meng-Yun Wei1Xiao-Ting Fan2Guo-Wei Zhou3School of Resources and Environmental Engineering, Anhui University, Hefei 230601, ChinaKey Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, ChinaKey Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, ChinaSchool of Resources and Environmental Engineering, Anhui University, Hefei 230601, ChinaNitrate-reducing iron(II) oxidation (NRFO) has been intensively reported in various bacteria. Iron(II) oxidation is found to be involved in both enzymatic and chemical reactions in nitrate-reducing Fe(II)-oxidizing microorganisms (NRFOMs). However, little is known about the relative contribution of biotic and abiotic reactions to iron(II) oxidation for the common nitrate reducers during the NRFO process. In this study, the typical nitrate reducers, four <i>Enterobacter</i> strains <i>E. hormaechei</i>, <i>E. tabaci</i>, <i>E. mori</i> and <i>E. asburiae</i>, were utilized as the model microorganisms. The comparison of the kinetics of nitrate, iron(II) and nitrite and N<sub>2</sub>O production in setups with and without iron(II) indicates a mixture of enzymatic and abiotic oxidation of iron(II) in all four <i>Enterobacter</i> strains. It was estimated that 22−29% of total oxidized iron(II) was coupled to microbial nitrate reduction by <i>E. hormaechei</i>, <i>E. tabaci</i>, <i>E. mori</i>, and <i>E. asburiae</i>. <i>Enterobacter</i> strains displayed an metabolic inactivity with heavy iron(III) encrustation on the cell surface in the NRFOmedium during days of incubation. Moreover, both respiratory and periplasmic nitrate-reducing genes are encoded by genomes of <i>Enterobacter</i> strains, suggesting that cell encrustation may occur with periplasmic iron(III) oxide precipitation as well as the surface iron(II) mineral coating for nitrate reducers. Overall, this study clarified the potential role of nitrate reducers in the biochemical cycling of iron under anoxic conditions, in turn, re-shaping their activity during denitrification because of cell encrustation with iron(III) minerals.https://www.mdpi.com/1420-3049/27/17/5581nitrate reducers<i>Enterobacter</i>enzymatic NRFOnitrate reductasesiron cycling |
| spellingShingle | Ming-Jun Li Meng-Yun Wei Xiao-Ting Fan Guo-Wei Zhou Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain Molecules nitrate reducers <i>Enterobacter</i> enzymatic NRFO nitrate reductases iron cycling |
| title | Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain |
| title_full | Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain |
| title_fullStr | Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain |
| title_full_unstemmed | Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain |
| title_short | Underestimation about the Contribution of Nitrate Reducers to Iron Cycling Indicated by <i>Enterobacter</i> Strain |
| title_sort | underestimation about the contribution of nitrate reducers to iron cycling indicated by i enterobacter i strain |
| topic | nitrate reducers <i>Enterobacter</i> enzymatic NRFO nitrate reductases iron cycling |
| url | https://www.mdpi.com/1420-3049/27/17/5581 |
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