The Genus Gallionella

Hanert, Hans H.

doi:10.1007/978-3-662-13187-9_40

Cited by 63 publications

(20 citation statements)

References 17 publications

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“…The apical cell, from which the stalk is terminally excreted (Hanert 1981), was not observed in our samples collected from natural habitats. Thus, only the stalk with its iron precipitates was the focus of this study.…”

Section: Resultscontrasting

confidence: 57%

“…The microenvironment within Gallionella biofilms on rock surface may be microaerophilic, but the ambient air has a normal saturation of oxygen. As pointed out by Hanert (1981) the main prerequisite for Gallionella growth is ferrous iron and not oxygen.…”

Section: Introductionmentioning

confidence: 98%

“…According to Hanert (1981) G. ferruginea is found at oxygen concentrations of 0.1-1% in water because it is living in gradient habitats of Fe (II) and Fe (III). It is considered to be a typical gradient organism, which requires well-defined techniques to grow cultures in the laboratory (Hallbeck, Stahl, and Pedersen 1993).…”

Section: Introductionmentioning

confidence: 99%

“…It is considered to be a typical gradient organism, which requires well-defined techniques to grow cultures in the laboratory (Hallbeck, Stahl, and Pedersen 1993). The natural habitat where these bacteria grow and produce stalks is a rather narrow Eh-pH environment with an Eh range of +200 to +380 mV (Hanert 1981). The pH of the environment is usually close to neutral or slightly alkaline.…”

Section: Introductionmentioning

confidence: 99%

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Biomineralization byGallionella

Hallberg

Ferris

2004

Geomicrobiology Journal

113

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A new environmental scanning electron microscopic (ESEM) technique at low vacuum (5 torr) and 99% humidity, where the sample never has been exposed to high vacuum and coating of carbon or gold, has revealed a new insight into the nature of iron mineralization that develops in association with the stalked bacteria Gallionella. The stalk fibers contain minute flaky iron precipitates. The size of the crystallites is 0.1-0.5 micron and some of them exhibit a hexagonal feature. EDAX analyses on individual crystallites give an atomic ratio between Fe and O very close to 0.67. The stoichiometric formula would thus be Fe 2 O 3 . Stoichiometry and crystallinity are in accordance with the mineral hematite. The mineralization seems to take place inside the fibers of the stalk. With time the Gallionella stalk is covered with iron oxihydroxides of different kinds that probably are controlled by inorganic processes more than by the organic chemistry of the stalk. From a thermodynamic point of view, oxygen as well as carbon dioxide are required to explain the formation of hematite inside the fibers. The precipitation takes probably place at a pH close to 5.

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Section: Resultscontrasting

confidence: 57%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Biomineralization byGallionella

Hallberg

Ferris

2004

Geomicrobiology Journal

113

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“…For stalk-or sheath-forming aerobic Fe(II)-oxidizing bacteria of the genera Gallionella and Leptothrix, it was suggested that microbially produced and excreted organic matrices are used for extra-cellular precipitation/binding of Fe(III) minerals produced during aerobic Fe(II) oxidation (Hanert 1981;Emerson and Revsbech 1994). This, however, still leaves open the questions i) where is Fe(II) oxidized (in the cytoplasm, in the periplasm, or at the cell surface?…”

Section: Introductionmentioning

confidence: 99%

Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria

Kappler

Johnson

Crosby

et al. 2010

Geochimica et Cosmochimica Acta

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Iron isotope fractionations produced during chemical and biological Fe(II) oxidation are sensitive to the proportions and nature of dissolved and solid-phase Fe species present, as well as the extent of isotopic exchange between precipitates and aqueous Fe. Iron isotopes therefore potentially constrain the mechanisms and pathways of Fe redox transformations in modern and ancient environments. In the present study, we followed in batch experiments Fe isotope fractionations between Fe(II) aq and Fe(III) oxide/hydroxide precipitates produced by the Fe(III) mineral encrusting, nitrate-reducing, Fe (II)-oxidizing Acidovorax sp. strain BoFeN1. Isotopic fractionation in 56 Fe/ 54 Fe approached that expected for equilibrium conditions, assuming an equilibrium Δ 56 Fe Fe(OH)3 -Fe(II)aq fractionation factor of +3.0 ‰. Previous studies have shown that Fe(II) oxidation by this Acidovorax strain occurs in the periplasm, and we propose that Fe isotope equilibrium is maintained through redox cycling via coupled electron and atom exchange between Fe(II) aq and Fe(III) precipitates in the contained environment of the periplasm. In addition to the apparent equilibrium isotopic fractionation, these experiments also record the kinetic effects of initial rapid oxidation, and possible phase transformations of the Fe(III) precipitates. Attainment of Fe isotope equilibrium between Fe(III) oxide/hydroxide precipitates and Fe(II) aq by neutrophilic, Fe(II)-oxidizing bacteria or through abiologic Fe(II) aq oxidation is generally not expected or observed, because the poor solubility of their metabolic product, i.e. Fe(III), usually leads to rapid precipitation of Fe(III) minerals, and hence expression of a kinetic fractionation upon precipitation; in the absence of redox cycling between Fe (II) aq and precipitate, kinetic isotope fractionations are likely to be retained. These results highlight the distinct Fe isotope fractionations that are produced by different pathways of biological and abiological Fe(II) oxidation.

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Evaluation of Microbial Components of Biofouling

Smith¹

2004

Water Encyclopedia

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Detecting the occurrence of biofouling and assessing its impact involve a range of analytical techniques, including informed observation and inspection of well components, interpretation of hydraulic and water quality testing, and direct analysis of microbial components of biofouling. The latter is the subject of this article. Symptoms: Indirect Analysis clogging (both formation/well and pump/discharge systems). corrosion alteration of water quality in pumped samples distinct coating on surfaces visible during inspections, such as borehole television surveys. Such symptoms are indications of biofouling and should trigger analysis to determine the nature of the biofouling.

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The Genus Gallionella

Cited by 63 publications

References 17 publications

Biomineralization byGallionella

Biomineralization byGallionella

Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria

Evaluation of Microbial Components of Biofouling

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