Microbes as Geologic Agents: Their Role in Mineral Formation

Ehrlich, Henry L.

doi:10.1080/014904599270659

Cited by 138 publications

(73 citation statements)

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“…Final calcite saturation indices for the ammonium carbonate and ammonium carbonate ϩ cells treatments were 1.0 and 1.4, respectively. One might have expected that the addition of bacterial cell surfaces, which are known to have high binding capacities for metals (Douglas and Beveridge, 1998) and can serve as mineral nucleation sites (Ehrlich, 1999), would enhance the precipitation rate, but we did not observe any such enhancement. Friis et al (2003) reported that B. subtilis cells caused decreased calcite saturation indices due to uptake of Ca on cell wall functional groups (Friis et al, 2003).…”

Section: Solution Chemistry Changescontrasting

confidence: 48%

Strontium incorporation into calcite generated by bacterial ureolysis

Fujita

Redden

Ingram

et al. 2004

Geochimica et Cosmochimica Acta

211

141

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Abstract-Strontium incorporation into calcite generated by bacterial ureolysis was investigated as part of an assessment of a proposed remediation approach for 90 Sr contamination in groundwater. Urea hydrolysis produces ammonium and carbonate and elevates pH, resulting in the promotion of calcium carbonate precipitation. Urea hydrolysis by the bacterium Bacillus pasteurii in a medium designed to mimic the chemistry of the Snake River Plain Aquifer in Idaho resulted in a pH rise from 7.5 to 9.1. Measured average distribution coefficients (D EX ) for Sr in the calcite produced by ureolysis (0.5) were up to an order of magnitude higher than values reported in the literature for natural and synthetic calcites (0.02-0.4). They were also higher than values for calcite produced abiotically by ammonium carbonate addition (0.3). The precipitation of calcite in these experiments was verified by X-ray diffraction. Time-of-flight secondary ion mass spectrometry (ToF SIMS) depth profiling (up to 350 nm) suggested that the Sr was not merely sorbed on the surface, but was present at depth within the particles. X-ray absorption near edge spectra showed that Sr was present in the calcite samples as a solid solution. The extent of Sr incorporation appeared to be driven primarily by the overall rate of calcite precipitation, where faster precipitation was associated with greater Sr uptake into the solid. The presence of bacterial surfaces as potential nucleation sites in the ammonium carbonate precipitation treatment did not enhance overall precipitation or the Sr distribution coefficient. Because bacterial ureolysis can generate high rates of calcite precipitation, the application of this approach is promising for remediation of 90 Sr contamination in environments where calcite is stable over the long term.

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Section: Solution Chemistry Changescontrasting

confidence: 48%

Strontium incorporation into calcite generated by bacterial ureolysis

Fujita

Redden

Ingram

et al. 2004

Geochimica et Cosmochimica Acta

211

141

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“…The low heavy metal pore water concentrations in these horizons suggest effective metal attenuation processes. 35 S tracer studies recently demonstrated that both of the reduced horizons have ongoing sulfate-reducing activity (32) and that the release of sulfide may have lead to the retention of metals as metal sulfides (13,15,21). Therefore, metabolically diverse sulfate reducers that can switch to Fe(III) reduction could fill an important niche in stratified contaminated soils.…”

mentioning

confidence: 99%

Heavy Metal Tolerance of Fe(III)-Reducing Microbial Communities in Contaminated Creek Bank Soils

Burkhardt

Bischoff

Akob

et al. 2011

Appl Environ Microbiol

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Toxic metals can be immobilized on surface sorption sites of soil Fe(III) minerals or can be included in the mineral structure (4, 29). Fe(III)-reducing bacteria (FeRB) can facilitate the release of these metals by reductive dissolution of Fe(III) oxides (9, 17) and bioreduction of Fe(III) oxide-bound trace metals (42). This release might enhance metal stress, suggesting that metal tolerance should be an important attribute for FeRB. Acidophilic FeRB can tolerate millimolar concentrations of Cd, Cu, Ni, and Zn (12), which might be a prerequisite to survival in habitats where low pH facilitates high metal solubility. In contrast, neutrophilic FeRB like Shewanella spp. tolerate only M concentrations (34, 36). Geobacter spp. have not been tested to the best of our knowledge, but metal tolerance proteins are expressed during growth in uranium-contaminated sediments, which might be connected to metal resistance (19).Near Ronneburg (Thuringia, Germany), uranium mining caused severe environmental contamination with metals and radionuclides (20). In creek bank alluvial soils of the Gessenbach, a main drainage system of upstream mining sites (41), high heavy metal concentrations occur both in solid phase and in the pore water of a ground-and surface water-influenced, oxidized, iron-rich Btlc horizon of a Luvic Gleysol. We demonstrated the solubilization of Co, Ni, Zn, As, and U in Btlc soil microcosms during biostimulated microbial Fe(III) reduction that was associated with the activity of microorganisms related to Delta-and Betaproteobacteria, Acidobacteria, and Firmicutes (7). The aims of this study were to (i) determine the heavy metal fraction of the solid phase, which could be released during reductive dissolution of Fe(III) oxides, (ii) estimate the effect of heavy metals on the activity of FeRB in the Gessenbach creek bank soil, and (iii) identify metal-tolerant FeRB, because the permanent exposure to contaminants during the last 50 years should have promoted metal tolerance.Soil geochemistry. Putative binding forms of heavy metals in the Btlc soil solid phase were determined by sequential extraction (8, 43) in samples collected in August 2006. Metal concentrations were analyzed with either ICP-MS (inductively coupled plasma-mass spectrometry) or ICP-OES (optical emission spectrometry) (8). Most metals (20 to 40%) and even 80% of As in Btlc soil were detected in fraction 5, which is representative for amorphous Fe(III) oxides (Fig. 1). A considerable amount of uranium (30%) was recovered in the specifically adsorbed fraction, whereas only Zn and Ni were primarily recovered in the mobile fraction. Zn and Ni also dominated the heavy metal pore water concentration of the creek bank soil, which was sampled monthly from June to November 2007 (7). Pore water heavy metal and As concentrations always peaked in the Btlc horizon (see Fig. S1 in the supplemental material) and reached maximum concentrations of 38.6, 16.4, 3.9, 1.5, 0.6, and 0.3 M for Zn, Ni, Al, Cu, Co, and Cd, respectively. Pore water Fe(II) concentrations, ...

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“…Different mechanisms of bacterial involvement in calcification have been proposed (23,24), and they have been a matter of controversy throughout the last century (54). It is generally accepted that this microbial activity can be influenced by environmental physical-chemical parameters, and it is correlated to both metabolic activities and cell surface structures (11,21,26).…”

mentioning

confidence: 99%

Bacillus subtilisGene Cluster Involved in Calcium Carbonate Biomineralization

et al. 2007

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Calcium carbonate precipitation, a widespread phenomenon among bacteria, has been investigated due to its wide range of scientific and technological implications. Nevertheless, little is known of the molecular mechanisms by which bacteria foster calcium carbonate mineralization. In our laboratory, we are studying calcite formation by Bacillus subtilis, in order to identify genes involved in the biomineralization process. A previous screening of UV mutants and of more than one thousand mutants obtained from the European B. subtilis Functional Analysis project allowed us to isolate strains altered in the precipitation phenotype. Starting from these results, we focused our attention on a cluster of five genes (lcfA, ysiA, ysiB, etfB, and etfA) called the lcfA operon. By insertional mutagenesis, mutant strains carrying each of the five genes were produced. All of them, with the exception of the strain carrying the mutated lcfA operon, were unable to form calcite crystals. By placing transcription under IPTG (isopropyl-␤-D-thiogalactopyranoside) control, the last gene, etfA, was identified as essential for the precipitation process. To verify cotranscription in the lcfA operon, reverse transcription-PCR experiments were performed and overlapping retrocotranscripts were found comprising three adjacent genes. The genes have putative functions linked to fatty acid metabolism. A link between calcium precipitation and fatty acid metabolism is suggested.

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Microbes as Geologic Agents: Their Role in Mineral Formation

Cited by 138 publications

References 0 publications

Strontium incorporation into calcite generated by bacterial ureolysis

Strontium incorporation into calcite generated by bacterial ureolysis

Heavy Metal Tolerance of Fe(III)-Reducing Microbial Communities in Contaminated Creek Bank Soils

Bacillus subtilisGene Cluster Involved in Calcium Carbonate Biomineralization

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