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Title: Bacillus lichenformis {gamma}-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction

Abstract

Complexation by microbially produced exopolymers may significantly impact the environmental mobility and toxicity of metals. This study focused on the conformational structure of the bacterial exopolymer, {gamma}-D-poly(glutamic acid) and its interactions with U(VI) examined using ATR-FTIR spectroscopy. Solution pH, polymer concentration, and ionic strength affected the conformation of the exopolymer, and U(VI) binding was monitored. At low pH, low concentration, or low ionic strength, this exopolymer exists in an {alpha}-helical conformation, while at high pH, concentration, or ionic strength the exopolymer exhibits a {beta}-sheet structure. The change in exopolymer conformation is likely to influence the number and nature of exposed surface functional groups, sites most responsible for metal complexation. The authors found the polyglutamate capsule binds U(VI) in a binuclear, bidentate fashion; in contrast the glutamate monomer forms a mononuclear, bidentate complex with U(VI). The apparent polynuclear binding of U(VI) may induce {beta}-sheet structure formation provided the U(VI) Concentration is sufficiently high.

Authors:
; ;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
OSTI Identifier:
20080509
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 34; Journal Issue: 9; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0013-936X
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; SOILS; GROUND WATER; REMEDIAL ACTION; BIODEGRADATION; URANIUM; INFRARED SPECTRA; FOURIER TRANSFORMATION; US DOE; BACILLUS

Citation Formats

He, L.M., Neu, M.P., and Vanderberg, L.A. Bacillus lichenformis {gamma}-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction. United States: N. p., 2000. Web. doi:10.1021/es991119e.
He, L.M., Neu, M.P., & Vanderberg, L.A. Bacillus lichenformis {gamma}-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction. United States. doi:10.1021/es991119e.
He, L.M., Neu, M.P., and Vanderberg, L.A. Mon . "Bacillus lichenformis {gamma}-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction". United States. doi:10.1021/es991119e.
@article{osti_20080509,
title = {Bacillus lichenformis {gamma}-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction},
author = {He, L.M. and Neu, M.P. and Vanderberg, L.A.},
abstractNote = {Complexation by microbially produced exopolymers may significantly impact the environmental mobility and toxicity of metals. This study focused on the conformational structure of the bacterial exopolymer, {gamma}-D-poly(glutamic acid) and its interactions with U(VI) examined using ATR-FTIR spectroscopy. Solution pH, polymer concentration, and ionic strength affected the conformation of the exopolymer, and U(VI) binding was monitored. At low pH, low concentration, or low ionic strength, this exopolymer exists in an {alpha}-helical conformation, while at high pH, concentration, or ionic strength the exopolymer exhibits a {beta}-sheet structure. The change in exopolymer conformation is likely to influence the number and nature of exposed surface functional groups, sites most responsible for metal complexation. The authors found the polyglutamate capsule binds U(VI) in a binuclear, bidentate fashion; in contrast the glutamate monomer forms a mononuclear, bidentate complex with U(VI). The apparent polynuclear binding of U(VI) may induce {beta}-sheet structure formation provided the U(VI) Concentration is sufficiently high.},
doi = {10.1021/es991119e},
journal = {Environmental Science and Technology},
issn = {0013-936X},
number = 9,
volume = 34,
place = {United States},
year = {2000},
month = {5}
}