Iron adsorption onto soil and aquatic bacteria: XAS structural study

Iron isotope fractionation during Fe(II) and Fe(III) adsorption on cyanobacteria

“…This is confirmed by the observation that the concentration of Fe(II) was stable in the abiotic sample at the same pH but without cyanobacteria (see González et al 2014 and Fe(III) solutions fits isotopic equilibrium (where the reaction components undergo isotopic exchange throughout the duration of the reaction) or Rayleigh isotopic fractionation (where the reaction product is isolated from further isotopic exchange with the system after formation), the data obtained herein were compared to the trends that would be expected for both models, following Criss (1999) and Allègre (2008). As can be seen from Figure 4, the interaction between Fe in different valence states fits an equilibrium isotopic fractionation model with α = 1.0027 for solutions containing Fe(II) and α = 1.0010 for solutions containing Fe(III).…”

“…In these cultures, the structural status of adsorbed Fe has been characterized in a recent in-situ X-ray Absorption Spectroscopy (XAS) study (González et al, 2014). We aimed to test the hypothesis that, similarly to other metals and in inorganic systems, Fe adsorption on bacterial phytoplankton cell surfaces is capable of producing significant isotopic fractionation with preferential adsorption of the heavy isotope on the biomass.…”

“…These fractions were quantitatively measured at the cell surfaces by using in-situ X-ray Absorption Spectroscopy and are equal to 25  2 % and 75  2 % for all three studied cyanobacteria, respectively (Table 1, González et al 2014 obtained in this work. Therefore, we conclude that aqueous, highly symmetric complexes…”

Divalent metal cation adsorption onto Leptothrix cholodnii SP-6SL bacterial cells

“…Metal adsorption onto bacteria has been measured for a wide range of bacterial species (e.g., Murray, 1976, 1980;Ferris and Beveridge, 1984;Fein et al, 1997;Daughney et al, 2001;Takahashi et al, 2005;Ngwenya and Chirwa, 2010;Gonzalez et al, 2014), but there have been no studies of metal adsorption behavior of Fe-oxidizing bacteria (FeOB). Although a wide range of bacterial species exhibit broadly similar metal adsorption behaviors (e.g., Yee and Fein, 2001;Kulczycki et al, 2003;Borrok et al, 2004;Kenney and Fein, 2011), the cell envelope of FeOB may exhibit markedly different adsorption behavior due to differences in cell wall composition (Wang et al, 1970).…”

Interaction of Freshwater Diatom with Gold Nanoparticles: Adsorption, Assimilation, and Stabilization by Cell Exometabolites

“…Thus, numerous studies have been devoted to the quantification and thermodynamic modeling of reversible metal cation adsorption on the cell wall of aquatic microorganisms [21][22][23][24]. Extensive research over past decades has provided a comprehensive picture of metal binding to cell walls of most model aquatic microorganisms, including autotrophic and heterotrophic bacteria and diatoms [25][26][27][28][29][30][31][32][33]. However, there is no study, to our knowledge, of AuNPs interaction with freshwater periphytic diatoms.…”