Formation of Sphalerite (ZnS) Deposits in Natural Biofilms of Sulfate-Reducing Bacteria

Labrenz, Matthias; Druschel, Gregory K.; Thomsen-Ebert, T.; Gilbert, Benjamin; Welch, Susan A.; Kemner, Kenneth M.; Logan, Graham A.; Summons, Roger E.; Stasió, Gelsomina De; Bond, Philip L.; Lai, Barry; Kelly, Shelly D.; Banfield, Jillian F.

doi:10.1126/science.290.5497.1744

Cited by 580 publications

(297 citation statements)

References 16 publications

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“…The surfaceattached communities (biofilms) increase resistance to antimicrobial agents compared to the resistance of free-swimming organisms (Hentzer et al, 2001) probably due to decreased metabolic activity within the depths of a biofilm (Spoering and Lewis, 2001) and to binding and sequestration of antimicrobial agents by biofilm components, such as negatively charged phosphate, sulfate, and carboxylic acid groups (Hunt, 1986). As biofilms facilitate sorption of heavy metals, they are capable of removing heavy metal ions from bulk liquid (Liehr et al 1994;Labrenz et al, 2000).…”

Section: The Mercury Uptake Is Ph-dependentmentioning

confidence: 99%

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

2017

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Mercury adsorption on the cell surface and intracellular uptake by bacteria represent the key first step in the production and accumulation of highly toxic mercury in living organisms. In this work, the biophysical characteristics of the mercury bioaccumulation are studied in intact cells of photosynthetic bacteria by use of analytical (dithizone) assay and physiological photosynthetic markers (pigment content, fluorescence induction and membrane potential) to determine the amount of mercury ions bound to the cell surface and taken up by the cell. It is shown that the Hg(II) uptake mechanism 1) has two kinetically distinguishable components, 2) includes co-opted influx through heavy metal transporters since the slow component is inhibited by Ca 2+ channel blockers, 3) shows complex pH-dependence demonstrating the competition of ligand binding of Hg(II) ions with H + ions (low pH) and high tendency of complex formation of Hg(II) with hydroxyl ions (high pH) and 4) is not a passive but an energy-dependent process as evidenced by light-activation and inhibition by protonophore. Photosynthetic bacteria can accumulate Hg(II) in amounts much (about 10 5 ) greater than their own masses by well defined strong and weak binding sites with equilibrium binding constants in the range of 1 (μM) -1 and 1 (mM) -1 , respectively. The strong binding sites are attributed to sulfhydryl groups as the uptake is blocked by use of sulfhydryl modifying agents and their number is much (two orders of magnitude) smaller than the number of weak binding sites. Biofilms developed by some bacteria (e.g. Rvx. gelatinosus) increase the mercury binding capacity further by a factor of about five. Photosynthetic bacteria in the light act as sponge of Hg(II) and can be potentially used for biomonitoring and bioremediation of mercury contaminated aqueous cultures.2

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Section: The Mercury Uptake Is Ph-dependentmentioning

confidence: 99%

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

2017

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“…doi: 10.1016/j.gca.2011.02.030 organism, but occurs in response to interactions between elements in bulk solution and metabolic exudates from the organism. For example, sulfate-reducing bacteria produce sulfide, which can react with aqueous Zn when released from the cell to precipitate extracellular sphalerite (ZnS) (Labrenz et al, 2000). In BCM, organisms expend energy to exert a direct control on precipitation, and the biominerals are used for a specific function and are typically located within a cell.…”

Section: Introductionmentioning

confidence: 99%

The effects of non-metabolizing bacterial cells on the precipitation of U, Pb and Ca phosphates

Dunham‐Cheatham

Xue

Bunker

et al. 2011

Geochimica et Cosmochimica Acta

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In this study, we test the potential for passive cell wall biomineralization by determining the effects of non-metabolizing bacteria on the precipitation of uranyl, lead, and calcium phosphates from a range of over-saturated conditions. Experiments were performed using Gram-positive Bacillus subtilis and Gram-negative Shewanella oneidensis MR-1. After equilibration, the aqueous phases were sampled and the remaining metal and P concentrations were analyzed using inductively coupled plasmaoptical emission spectroscopy (ICP-OES); the solid phases were collected and analyzed using X-ray diffractometry (XRD), transmission electron microscopy (TEM), and X-ray absorption spectroscopy (XAS).At the lower degrees of over-saturation studied, bacterial cells exerted no discernable effect on the mode of precipitation of the metal phosphates, with homogeneous precipitation occurring exclusively. However, at higher saturation states in the U system, we observed heterogeneous mineralization and extensive nucleation of hydrogen uranyl phosphate (HUP) mineralization throughout the fabric of the bacterial cell walls. This mineral nucleation effect was observed in both B. subtilis and S. oneidensis cells. In both cases, the biogenic mineral precipitates formed under the higher saturation state conditions were significantly smaller than those that formed in the abiotic controls.The cell wall nucleation effects that occurred in some of the U systems were not observed under any of the saturation state conditions studied in the Pb or Ca systems. The presence of B. subtilis significantly decreased the extent of precipitation in the U system, but had little effect in the Pb and Ca systems. At least part of this effect is due to higher solubility of the nanoscale HUP precipitate relative to macroscopic HUP. This study documents several effects of non-metabolizing bacterial cells on the nature and extent of metal phosphate precipitation. Each of these effects likely contributes to higher metal mobilities in geologic media, but the effects are not universal, and occur only with some elements and only under a subset of the conditions studied.

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“…Radionuclides can be immobilized through interactions between microbially-produced sulfide (White, Sharman, & Gadd, 1998;Lebranz et al, 2000) and phosphate (Macaskie et al, 1992;Boswell, Dick, & Macaskie, 1999;Jeong & Macaskie, 1999), or through bacterial iron oxidation (Banfield et al, 2000) in the general process of biomineralization (Martinez et al, 2007). Uranium phosphate precipitation has been facilitated by diverse bacterial genera including Arthrobacter, BacillusI, Rahnella, Deinococcus, Escherichia and Pseudomonas (Basnakova et al,24 1998; Powers et al, 2002;Appukuttan, Rao, & Apte, 2006).…”

Section: Radionuclide Bioprecipitation By Urease-producing Bacteriamentioning

confidence: 99%