Biosorption sites of selected metals using electron microscopy

Tsezos, M.; Remoudaki, E.; Angelatou, V.

doi:10.1016/s0300-9629(97)00009-1

Cited by 28 publications

(13 citation statements)

References 16 publications

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“…As suggested by previous studies, the biosorption and bioreduction of silver ions could occur on the cell wall; 7,16 it is possible to hypothesize that [Ag(NH 3 ) 2 ]…”

Section: Observation Of Silver Nanoparticlesmentioning

confidence: 77%

Biosorption and bioreduction of diamine silver complex by Corynebacterium

Zhang

et al. 2004

J of Chemical Tech & Biotech

172

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Corynebacterium strain SH09 separated from a silver mine was used for biosorption and bioreduction of diamine silver complex. The biosorption of the diamine silver complex was better than that of silver ions and the maximum of the former was about 350 (mg Ag) (g dried biomass) −1 . After dried cells of SH09 were resuspended in the aqueous solution of diamine silver complex in the dark at 60• C for more than 72 h, transmission electron microscopy (TEM) observations showed that a large quantity of black particles whose diameter ranged from 10 to 15 nm were formed on the cell wall. The particles were identified as being silver nanoparticles by X-ray diffraction (XRD) and UV-vis spectroscopy. Under the same conditions, no bioreduction of silver nitrate was found. According to IR spectra, some functional groups, such as the amide of the proteins, were involved in the processes of biosorption and bioreduction.

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“…As suggested by previous studies, the biosorption and bioreduction of silver ions could occur on the cell wall; 7,16 it is possible to hypothesize that [Ag(NH 3 ) 2 ]…”

Section: Observation Of Silver Nanoparticlesmentioning

confidence: 77%

Biosorption and bioreduction of diamine silver complex by Corynebacterium

Zhang

et al. 2004

J of Chemical Tech & Biotech

172

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“…In addition, it is possible that Ag + could have also been reduced by residual Fe 2+ in both experimental systems (Reaction (5)). Increased metal concentrations are known to cause cell lyses thereby releasing intracellular material that could act as additional reductants that contribute to the formation of Ag (and Au) nanoparticles (Reaction (6)) [58][59][60]. In the natural environment, however, Ag nanoparticles would likely be unstable for prolonged periods of time as they would also be subjected to dissolution processes [61][62][63][64].…”

Section: Microbially-catalyzed Ag Immobilizationmentioning

confidence: 99%

Biogeochemical Cycling of Silver in Acidic, Weathering Environments

et al. 2017

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Under acidic, weathering conditions, silver (Ag) is considered to be highly mobile and can be dispersed within near-surface environments. In this study, a range of regolith materials were sampled from three abandoned open pit mines located in the Iberian Pyrite Belt, Spain. Samples were analyzed for Ag mineralogy, content, and distribution using micro-analytical techniques and high-resolution electron microscopy. While Ag concentrations were variable within these materials, elevated Ag concentrations occurred in gossans. The detection of Ag within younger regolith materials, i.e., terrace iron formations and mine soils, indicated that Ag cycling was a continuous process. Microbial microfossils were observed within crevices of gossan and their presence highlights the preservation of mineralized cells and the potential for biogeochemical processes contributing to metal mobility in the rock record. An acidophilic, iron-oxidizing microbial consortium was enriched from terrace iron formations. When the microbial consortium was exposed to dissolved Ag, more than 90% of Ag precipitated out of solution as argentojarosite. In terms of biogeochemical Ag cycling, this demonstrates that Ag re-precipitation processes may occur rapidly in comparison to Ag dissolution processes. The kinetics of Ag mobility was estimated for each type of regolith material. Gossans represented 0.6-146.7 years of biogeochemical Ag cycling while terrace iron formation and mine soils represented 1.9-42.7 years and 0.7-1.6 years of Ag biogeochemical cycling, respectively. Biogeochemical processes were interpreted from the chemical and structural characterization of regolith material and demonstrated that Ag can be highly dispersed throughout an acidic, weathering environment.

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“…Mycorrhizal roots showed a 5-fold increase in Cu in the pectin plus hemicellulose 1 fraction, which mirrored a reduction in the binding in the hemicellulose 2 fraction (Table 2). In general, the absorption of Cu by fungi and other microorganisms is a process which consists of two phases (Kapoor and Viraraghavan, 1995;Morley and Gadd, 1995;Tsezos et al, 1997;Blaudez et al, 2000;Gonzalez-Chavez et al, 2002): (a) a rapid phase, which represents the binding of Cu to accessible exchange sites on the surfaces of cell walls or (b) a slower phase where Cu diffuses into the porous cell wall structure and is sequestered or removed by other processes until an equilibrium is reached. In this study, Cu-sorption was a rapid process not only in the cell walls of intact roots but also in the purified cell wall fractions (Fig.…”

Section: Characteristics Of Cu Binding In Cell Wallsmentioning

confidence: 99%

Arbuscular mycorrhizal colonisation increases copper binding capacity of root cell walls of Oryza sativa L. and reduces copper uptake

Zhang

Lin

Gao

et al. 2009

Soil Biology and Biochemistry

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a b s t r a c tThere is evidence that colonisation by mycorrhizal fungi can protect host plants from toxic concentrations of heavy metals. The mechanism by which protection is provided by the fungus for any particular metal is poorly understood. Rice (Oryza sativa L.) plants were inoculated with Glomus mosseae and grown for 4 weeks to ensure strong colonisation. The plants were then exposed to low to toxic concentrations of copper (Cu) and the uptake and distribution were examined. The effect of mycorrhizal colonisation on the cell wall composition and Cu binding capacity of roots was also investigated. Mycorrhizal plants showed moderate reductions in Cu concentrations in roots but large reductions in shoots. In roots, mycorrhizal plants accumulated more Cu in cell walls but much less in the symplasm compared to nonmycorrhizal plants. The differences in cell wall binding of Cu could be partly explained by changes in the composition of the cell wall. The mechanistic basis for the reduced Cu accumulation and the potential beneficial consequences of mycorrhizal associations on plant growth in Cu toxic soil are discussed.

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Biosorption sites of selected metals using electron microscopy

Cited by 28 publications

References 16 publications

Biosorption and bioreduction of diamine silver complex by Corynebacterium

Biosorption and bioreduction of diamine silver complex by Corynebacterium

Biogeochemical Cycling of Silver in Acidic, Weathering Environments

Arbuscular mycorrhizal colonisation increases copper binding capacity of root cell walls of Oryza sativa L. and reduces copper uptake

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