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Interaction between ferrihydrite and nitrate respirations by Shewanella oneidensis MR-1

Paper ID Volume ID Publish Year Pages File Format Full-Text
34295 45016 2015 5 PDF Available
Title
Interaction between ferrihydrite and nitrate respirations by Shewanella oneidensis MR-1
Abstract

•Low-level NO3− increased HFO reduction rate through stimulating cell activity.•NO2- was harmful to cell respiration through inhibiting HFO and NO3- reduction.•Low-level NO3− has a synergistic effect with the iron respiration in Shewanella.

Shewanella oneidensis MR-1 is a model dissimilatory iron reducing bacterium and plays an important role in bioremediation and biogeochemical cycling of elements. Understanding the potential interaction between iron and nitrate respirations by S. oneidensis MR-1 is of great significance for environmental bioremediation. In this paper, the stimulating effect of nitrate on iron reduction by S. oneidensis MR-1 was reported, which was different from previous reports. Nitrate at environmentally relevant concentrations (e.g., <2 mM) significantly enhanced the reduction of iron oxides, while nitrate at a higher concentration was detrimental to such a reduction. In the absence of nitrate, mutants of ΔnapB and ΔnrfA exhibited a more rapid iron oxides reduction than the wild type strain (WT). In the presence of 2 mM nitrate, ΔnapB showed a promoted reduction ability, but ΔnrfA completely lost such a capability. Furthermore, after dosing 2 mM nitrate, both WT and ΔnapB generated more ATP while ΔnrfA exhibited a reduced ATP production. This study demonstrates that nitrate respiration affected iron respiration of S. oneidensis MR-1 in a complex manner and its nitrate- and iron-respiration properties endowed this strain a great flexibility and adaptability to the fluctuation and availability of nitrate and iron.

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Keywords
Shewanella oneidensis MR-1; Bioreduction; Iron oxide; Nitrate; Respiration activity
First Page Preview
Interaction between ferrihydrite and nitrate respirations by Shewanella oneidensis MR-1
Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 50, Issue 11, November 2015, Pages 1942–1946
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering