title: [Mechanism of interaction between Ag+ and Saccharomyces cerevisiae].
abstract: To understand the characteristics of Ag+ biosorption by the waste biomass of Saccharomyces cerevisiae, the release phenomena of the cell physiological cations, such as K+, Mg2+, Ca2+, Na+, and pH value change during Ag+ uptake were investigated. The presence of Ag+ promoted the release of the cations, and decreased the absorption of H+. Ion exchange was one of the mechanisms involved in metal-microbe interaction. Ag+ also exhibited a degree covalent binding with the biomass. Both Ag+ uptake and cation release (K+, Mg2+, Ca2+ or Na+) followed the pseudo-second order kinetics. Fourier transform infrared spectroscopy (FTIR) indicated that the carboxyl group on the surface of the cells could play important role in metal-microbe interaction. The scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX) and transmission electron microscopy with energy-dispersive X-ray analysis (TEM-EDX) were used to directly observe the change of the component elements and surface configuration of the cells before and after the interaction of the microbe with Ag+, and the results proved that Ag+ was adsorbed by the cell surface. Simultaneously, the precipitate containing Ag with higher concentration than the surface-adsorbed Ag was formed on the cell surface also resulted in the removal of Ag+ from the aqueous solution.
authors.affiliation: Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, China. chencan@tsinghua.edu.cn
authors.forename: Can
authors.initials: C
authors.lastname: Chen
authors.forename: Jian-long
authors.initials: JL
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D002412:Cations / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D012834:Silver / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D002412:Cations; D014874:Water Pollutants, Chemical; D012834:Silver