scholarly journals Electron Donor Utilization and Secondary Mineral Formation during the Bioreduction of Lepidocrocite by Shewanella putrefaciens CN32

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 434 ◽  
Author(s):  
Edward J. O’Loughlin ◽  
Christopher A. Gorski ◽  
Theodore M. Flynn ◽  
Michelle M. Scherer
Keyword(s):  
Electron Donor ◽  
Geochemical Modeling ◽  
Shewanella Putrefaciens ◽  
Green Rust ◽  
Electron Donors ◽  
Secondary Mineral ◽  
Secondary Minerals ◽  
Iron Reducing Bacteria ◽  
Carbonate Concentration ◽  
Geochemical Factors

The bioreduction of Fe(III) oxides by dissimilatory iron reducing bacteria (DIRB) may result in the production of a suite of Fe(II)-bearing secondary minerals, including magnetite, siderite, vivianite, green rusts, and chukanovite; the formation of specific phases controlled by the interaction of various physiological and geochemical factors. In an effort to better understand the effects of individual electron donors on the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of a series of potential electron donors on the bioreduction of lepidocrocite (γ-FeOOH) by Shewanella putrefaciens CN32. Biomineralization products were identified by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. Acetate, citrate, ethanol, glucose, glutamate, glycerol, malate, and succinate were not effectively utilized for the bioreduction of lepidocrocite by S. putrefaciens CN32; however, substantial Fe(II) production was observed when formate, lactate, H2, pyruvate, serine, or N acetylglucosamine (NAG) was provided as an electron donor. Carbonate or sulfate green rust was the dominant Fe(II)-bearing secondary mineral when formate, H2, lactate, or NAG was provided, however, siderite formed with pyruvate or serine. Geochemical modeling indicated that pH and carbonate concentration are the key factors determining the prevalence of carbonate green rust verses siderite.

scholarly journals Effects of Fe(III) Oxide Mineralogy and Phosphate on Fe(II) Secondary Mineral Formation during Microbial Iron Reduction

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 149
Author(s):  
Edward J. O’Loughlin ◽  
Maxim I. Boyanov ◽  
Christopher A. Gorski ◽  
Michelle M. Scherer ◽  
Kenneth M. Kemner
Keyword(s):  
Iron Reduction ◽  
Phosphate Concentration ◽  
Green Rust ◽  
Mineral Formation ◽  
Secondary Mineral ◽  
X Ray Diffraction ◽  
Secondary Minerals ◽  
Iron Reducing Bacteria ◽  
Secondary Mineral Formation ◽  
Reducing Bacteria

The bioreduction of Fe(III) oxides by dissimilatory iron-reducing bacteria may result in the formation of a suite of Fe(II)-bearing secondary minerals, including magnetite (a mixed Fe(II)/Fe(III) oxide), siderite (Fe(II) carbonate), vivianite (Fe(II) phosphate), chukanovite (ferrous hydroxy carbonate), and green rusts (mixed Fe(II)/Fe(III) hydroxides). In an effort to better understand the factors controlling the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of Fe(III) oxide mineralogy, phosphate concentration, and the availability of an electron shuttle (9,10-anthraquinone-2,6-disulfonate, AQDS) on the bioreduction of a series of Fe(III) oxides (akaganeite, feroxyhyte, ferric green rust, ferrihydrite, goethite, hematite, and lepidocrocite) by Shewanella putrefaciens CN32, and the resulting formation of secondary minerals, as determined by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. The overall extent of Fe(II) production was highly dependent on the type of Fe(III) oxide provided. With the exception of hematite, AQDS enhanced the rate of Fe(II) production; however, the presence of AQDS did not always lead to an increase in the overall extent of Fe(II) production and did not affect the types of Fe(II)-bearing secondary minerals that formed. The effects of the presence of phosphate on the rate and extent of Fe(II) production were variable among the Fe(III) oxides, but in general, the highest loadings of phosphate resulted in decreased rates of Fe(II) production, but ultimately higher levels of Fe(II) than in the absence of phosphate. In addition, phosphate concentration had a pronounced effect on the types of secondary minerals that formed; magnetite and chukanovite formed at phosphate concentrations of ≤1 mM (ferrihydrite), <~100 µM (lepidocrocite), 500 µM (feroxyhyte and ferric green rust), while green rust, or green rust and vivianite, formed at phosphate concentrations of 10 mM (ferrihydrite), ≥100 µM (lepidocrocite), and 5 mM (feroxyhyte and ferric green rust). These results further demonstrate that the bioreduction of Fe(III) oxides, and accompanying Fe(II)-bearing secondary mineral formation, is controlled by a complex interplay of mineralogical, geochemical, and microbiological factors.

scholarly journals A Microcosm Treatability Study for Evaluating Wood Mulch-Based Amendments as Electron Donors for Trichloroethene (TCE) Reductive Dechlorination

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1949
Author(s):  
Edoardo Masut ◽  
Alessandro Battaglia ◽  
Luca Ferioli ◽  
Anna Legnani ◽  
Carolina Cruz Viggi ◽  
...  
Keyword(s):  
Electron Donor ◽  
Environmental Sustainability ◽  
Reductive Dechlorination ◽  
Environmental Remediation ◽  
Low Cost ◽  
Chlorinated Solvents ◽  
Electron Donors ◽  
Chlorinated Ethenes ◽  
Dehalococcoides Mccartyi ◽  
Wood Mulch

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes.

Microbial Perchlorate Reduction in Groundwater with Different Electron Donors

2013 ◽  
Vol 295-298 ◽  
pp. 1402-1407
Author(s):  
Rui Wang ◽  
Ming Chen ◽  
Jia Wen Zhang ◽  
Fei Liu ◽  
Hong Han Chen
Keyword(s):  
Removal Efficiency ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Reduction Rate ◽  
Electron Donors ◽  
Monod Equation ◽  
Hydrogen Addition ◽  
Perchlorate Reduction ◽  
Perchlorate Removal

Effects of different electron donors (acetate and hydrogen), acetate and perchlorate concentrations on microbial perchlorate reduction in groundwater were studied. The results showed that acetate and hydrogen addition as an electron donor can significantly improve perchlorate removal efficiency while a longer period was observed for hydrogen (15 d) than for acetate (8 d). The optical ratio of electron donor (acetate)-to-electron acceptor (perchlorate) was approximately 1.65 mg COD mg perchlorate-1. The highest specific reduction rate of perchlorate was achieved at the acetate-to-perchlorate ratio of 3.80 mg COD mg perchlorate-1. The perchlorate reduction rates corresponded well to the theoretical values calculated by the Monod equation and the parameters of Ks and Vm were determined to be 15.6 mg L-1 and 0.26 d-1, respectively.

Photocatalytic CO2 reduction using water as an electron donor by a powdered Z-scheme system consisting of metal sulfide and an RGO–TiO2 composite

2017 ◽  
Vol 198 ◽  
pp. 397-407 ◽  
Author(s):  
Tomoaki Takayama ◽  
Ko Sato ◽  
Takehiro Fujimura ◽  
Yuki Kojima ◽  
Akihide Iwase ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Visible Light ◽  
Water Splitting ◽  
Electron Donor ◽  
Visible Light Irradiation ◽  
Co2 Reduction ◽  
Metal Sulfide ◽  
Electron Donors ◽  
Reduced Graphene

CuGaS2, (AgInS2)x–(ZnS)2−2x, Ag2ZnGeS4, Ni- or Pb-doped ZnS, (ZnS)0.9–(CuCl)0.1, and ZnGa0.5In1.5S4 showed activities for CO2 reduction to form CO and/or HCOOH in an aqueous solution containing K2SO3 and Na2S as electron donors under visible light irradiation. Among them, CuGaS2 and Ni-doped ZnS photocatalysts showed relatively high activities for CO and HCOOH formation, respectively. CuGaS2 was applied in a powdered Z-scheme system combining with reduced graphene oxide (RGO)-incorporated TiO2 as an O2-evolving photocatalyst. The powdered Z-scheme system produced CO from CO2 in addition to H2 and O2 due to water splitting. Oxygen evolution with an almost stoichiometric amount indicates that water was consumed as an electron donor in the Z-schematic CO2 reduction. Thus, we successfully demonstrated CO2 reduction of artificial photosynthesis using a simple Z-scheme system in which two kinds of photocatalyst powders (CuGaS2 and an RGO–TiO2 composite) were only dispersed in water under 1 atm of CO2.

ELECTRON DONORS AND COFAGTORS FOR DENITRIFIGATION BY PSEUDOMONAS PERFECTOMARINUS

1963 ◽  
Vol 9 (6) ◽  
pp. 799-807 ◽  
Author(s):  
Martha Rhodes ◽  
Audrey Best ◽  
W. J. Payne
Keyword(s):  
Amino Acids ◽  
Electron Donor ◽  
Electron Donors ◽  
Resting Cells ◽  
Test Compound ◽  
Whole Cell ◽  
Minimal Media

Pseudomonas perfectomarinus released nitrogen fiom nitrate in media containing a variety of amino acids, pyruvate, or urea, but only if these minimal media were supplemented with glucose or, preferably, citrate. L-Arabinose (and to a lesser degree, D-arabinose) served as electron donor in combination with glucose or citrate, whereas other sugars did not. Asparagine, however, was the most effective oxidizable substrate tested and was the only test compound supporting denitrification without supplementary glucose or citrate. Mano-metric experiments revealed that adapted resting cells liberated nitrogen very rapidly with asparagine but less rapidly with citrate. Furthermore, cell-free extracts of adapted bacteria denitrified nitrate when provided with these substrates. Flavine mononucleotide was more effective as a stimulatory cofactor for denitrification than flavine adenine dinucleotide in whole-cell experiments, but not with cell-free extracts. Experiments with dialyzed cell-free extracts revealed that the enzymes which oxidized asparagine and citrate (or actually isocitrate) were linked with triphosphopyridine nucleotide. Additional experiments with cell-free extracts revealed that oxidation of reduced triphosphopyridine nucleotide was enzymatically linked with flavine mononucleotide.

Microbial Reduction of Lepidocrocite γ-FeOOH by Shewanella putrefaciens; The Formation of Green Rust

2002 ◽  
pp. 231-237
Author(s):  
G. Ona-Nguema ◽  
M. Abdelmoula ◽  
F. Jorand ◽  
O. Benali ◽  
A. Géhin ◽  
...  
Keyword(s):  
Shewanella Putrefaciens ◽  
Microbial Reduction ◽  
Green Rust

scholarly journals Abundance of Fe(III) during cultivation affects the microbiologically influenced corrosion (MIC) behaviour of iron reducing bacteria Shewanella putrefaciens

2020 ◽  
Vol 174 ◽  
pp. 108855
Author(s):  
Nina Wurzler ◽  
Jan David Schutter ◽  
Ralph Wagner ◽  
Matthias Dimper ◽  
Dirk Lützenkirchen-Hecht ◽  
...  
Keyword(s):  
Shewanella Putrefaciens ◽  
Microbiologically Influenced Corrosion ◽  
Iron Reducing Bacteria ◽  
Reducing Bacteria

scholarly journals Diversity and Ubiquity of Bacteria Capable of Utilizing Humic Substances as Electron Donors for Anaerobic Respiration

2002 ◽  
Vol 68 (5) ◽  
pp. 2445-2452 ◽  
Author(s):  
John D. Coates ◽  
Kimberly A. Cole ◽  
Romy Chakraborty ◽  
Susan M. O'Connor ◽  
Laurie A. Achenbach
Keyword(s):  
Energy Source ◽  
Carbon Source ◽  
Humic Substances ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Electron Donors ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Couple Growth ◽  
Probable Number

ABSTRACT Previous studies have demonstrated that reduced humic substances (HS) can be reoxidized by anaerobic bacteria such as Geobacter, Geothrix, and Wolinella species with a suitable electron acceptor; however, little is known of the importance of this metabolism in the environment. Recently we investigated this metabolism in a diversity of environments including marine and aquatic sediments, forest soils, and drainage ditch soils. Most-probable-number enumeration studies were performed using 2,6-anthrahydroquinone disulfonate (AHDS), an analog for reduced HS, as the electron donor with nitrate as the electron acceptor. Anaerobic organisms capable of utilizing reduced HS as an electron donor were found in all environments tested and ranged from a low of 2.31 × 101 in aquifer sediments to a high of 9.33 × 106 in lake sediments. As part of this study we isolated six novel organisms capable of anaerobic AHDS oxidation. All of the isolates coupled the oxidation of AHDS to the reduction of nitrate with acetate (0.1 mM) as the carbon source. In the absence of cells, no AHDS oxidation was apparent, and in the absence of AHDS, no cell density increase was observed. Generally, nitrate was reduced to N2. Analysis of the AHDS and its oxidized form, 2,6-anthraquinone disulfonate (AQDS), in the medium during growth revealed that the anthraquinone was not being biodegraded as a carbon source and was simply being oxidized as an energy source. Determination of the AHDS oxidized and nitrate reduced accounted for 109% of the theoretical electron transfer. In addition to AHDS, all of these isolates could also couple the oxidation of reduced humic substances to the reduction of nitrate. No HS oxidation occurred in the absence of cells and in the absence of a suitable electron acceptor, demonstrating that these organisms were capable of utilizing natural HS as an energy source and that AHDS serves as a suitable analog for studying this metabolism. Alternative electron donors included simple volatile fatty acids such as propionate, butyrate, and valerate as well as simple organic acids such as lactate and pyruvate. Analysis of the complete sequences of the 16S rRNA genes revealed that the isolates were not closely related to each other and were phylogenetically diverse, with members in the alpha, beta, gamma, and delta subdivisions of the Proteobacteria. Most of the isolates were closely related to known genera not previously recognized for their ability to couple growth to HS oxidation, while one of the isolates represented a new genus in the delta subclass of the Proteobacteria. The results presented here demonstrate that microbial oxidation of HS is a ubiquitous metabolism in the environment. This study represents the first description of HS-oxidizing isolates and demonstrates that microorganisms capable of HS oxidation are phylogenetically diverse.

Modes and textures of secondary minerals on Chinese coins of different ages

2003 ◽  
Vol 67 (1) ◽  
pp. 23-29 ◽  
Author(s):  
J. N. Fang ◽  
L. P. Tan ◽  
E. Huang
Keyword(s):  
Qing Dynasty ◽  
Ming Dynasty ◽  
Song Dynasty ◽  
Secondary Mineral ◽  
Secondary Minerals ◽  
The Qing Dynasty ◽  
The Song Dynasty ◽  
Different Ages ◽  
The Ming Dynasty

AbstractA thorough assessment of the secondary minerals on 796 Chinese Pb-Cu-Sn-Zn bronze coins from ∼1100 BC to AD 1911 has been made. Malachite is found on more than 80% of the coins irrespective of their dynasties, but a botryoidal texture is only observed on the coins of the Song dynasty or older. Azurite, however, is seen in microscopic quantities on a single coin of ∼AD 1800, but is clearly visible on the Ming dynasty or older coins. Cerussite is a common secondary mineral of the Qin dynasty and older coins, though it has not been found on the Qing dynasty or younger coins. Cuprite is observed on the Song dynasty and older coins.

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