GEOC 3 |
| The adsorption of bacterial exopolysaccharides (EPS) on the mineral surfaces has important consequences in soils. EPS have the ability to spontaneously adsorb onto mineral surfaces, leading to stable organic-inorganic aggregates. In consequence, these complexes allow the survival of soil bacteria, and contribute to the soil fertilization by modifying its physicochemical properties. In this work, molecular dynamics simulations are used to explore the interactions between several EPS and a sodium montmorillonite surface. The considered EPS are: Dextran, MWAP71, RMDP17, Rhamsan, Xanthan and Succinoglycan. These EPS exhibit a structural diversity in the composition of sugar monomers, the global charge and in the occurrence of branches. The enthalpies of adsorption of the different EPS are estimated and the influence of the chemical and structural factors is explored. The results obtained at the molecular scale favourably compare with the macroscopic experimental data that evidenced the aggregating property of the EPS Na-montmorillonite systems. |
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Frontiers in Geochemistry: Commemorating the 25th Anniversary of the ACS-Geochemistry Division
9:00 AM-11:55 AM, Sunday, 10 September 2006 Moscone Center -- Room 262, Oral
Sci-Mix
Division of Geochemistry |