Adsorption of cadmium to Bacillus subtilis bacterial cell walls: a pH-dependent X-ray absorption fine structure spectroscopy study

Boyanov, M. I. and Kelly, S. D. and Kemner, K. M. and Bunker, B. A. and Fein, J. B. and Fowle, D. A. (2003) Adsorption of cadmium to Bacillus subtilis bacterial cell walls: a pH-dependent X-ray absorption fine structure spectroscopy study. Geochimica et Cosmochimica Acta, 67 (18). 3299 - 3311. ISSN 1810-522X

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Official URL: https://doi.org/10.1016/S0016-7037(02)01343-1

Abstract

The local atomic environment of Cd bound to the cell wall of the gram-positive bacterium Bacillus subtilis was determined by X-ray absorption fine structure (XAFS) spectroscopy. Samples were prepared at six pH values in the range 3.4 to 7.8, and the bacterial functional groups responsible for the adsorption were identified under each condition. Under the experimental Cd and bacterial concentrations, the spectroscopy results indicate that Cd binds predominantly to phosphoryl ligands below pH 4.4, whereas at higher pH, adsorption to carboxyl groups becomes increasingly important. At pH 7.8, we observe the activation of an additional binding site, which we tentatively ascribe to a phosphoryl site with smaller Cd-P distance than the one that is active at lower pH conditions. XAFS spectra of several cadmium acetate, phosphate, and perchlorate solutions were measured and used as standards for fingerprinting, as well as to assess the ability of FEFF8 and FEFFIT to model carboxyl, phosphoryl, and hydration environments, respectively. The results of this XAFS study in general corroborate existing surface complexation models; however, some binding mechanism details could only be detected with the XAFS technique.

Item Type: Article
Subjects: F Earth Science > Geology
Divisions: Department of > Earth Science
Depositing User: lpa manjunath user
Date Deposited: 07 Sep 2019 05:46
Last Modified: 07 Sep 2019 05:46
URI: http://eprints.uni-mysore.ac.in/id/eprint/7718

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