期刊
ENVIRONMENTAL SCIENCE & TECHNOLOGY
卷 40, 期 6, 页码 1806-1813出版社
AMER CHEMICAL SOC
DOI: 10.1021/es050981l
关键词
-
The acid-base and Zn sorption properties of three bacteria, Cuprialvidus metallidurans CH34, Pseudomonas putida ATCC112633, and Escherichia coli K12DH5 alpha, were investigated through an original combination of extended X-ray absorption fine structure (EXAFS) spectroscopy and equilibrium titration studies. Acid-base titration curves of the three strains were fitted with a model accounting for three conceptual reactive sites: an acidic (carboxyl and/or phosphodiester), a neutral (phosphomonoester), and a basic (amine and/or hydroxyl) group. Calculated proton and Zn equilibrium constants and site densities compare with literature data. The nature of Zn binding sites was studied by EXAFS spectroscopy. Phosphoester, carboxyl, and unexpectedly sulfhydryl ligands were identified. Their proportions depended on Zn loading and bacterial strain and were consistent with the titration results, These findings were compared to the structure and site density of the major cell wall components. It appeared that the cumulated theoretical site density of these structures (< 2 Zn nm(-2)) was much lower than the total site density of the investigated strains (16-56 Zn nm(-2)). These results suggest a dominant role of extracellular polymeric substances in Zn retention processes, although Zn binding to inner cell components cannot be excluded.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据