https://scholars.lib.ntu.edu.tw/handle/123456789/407738
標題: | Fluorescent quenching for biofilm extracellular polymeric substances (EPS) bound with Cu(II) | 作者: | Zhang D. Lee D.-J. Pan X. |
關鍵字: | Binding;Copper;Extracellular polymeric substances;Fluorescence quenching titration | 公開日期: | 2012 | 卷: | 43 | 期: | 3 | 起(迄)頁: | 450-454 | 來源出版物: | Journal of the Taiwan Institute of Chemical Engineers | 摘要: | The Cu(II) binding properties of loosely bound extracellular polymeric substances (LBEPSs) and tightly bound EPSs (TBEPSs) extracted from biofilm samples at two apparent molecular weight (AMW) ranges, >14kDa and 1-14kDa, were investigated using three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy. The protein-like and aromatic protein fluorescence peaks were identified in EEM fluorescence spectra as peaks A and B, respectively. The intensities of peaks A and B were generally quenched when Cu(II) was bound with LBEPSs or TBEPSs with AMWs>14kDa at various pH levels. Conversely, for 1-14kDa EPSs, fluorescence intensities of peaks A and B were not quenched when Cu(II) was bound with LBEPSs at pH 4 or with both LBEPSs and TBEPSs at pH 8. The Stern-Volmer constant (logK sv) for the Cu(II)-LBEPSs and Cu(II)-TBEPSs binding processes were 2.38-4.37. The capability of EPSs to bind with Cu(II) increased as pH increased. At pH>4, the protein-like substances and aromatic proteins in TBEPSs had greater Cu(II) binding capability than LBEPSs. Additionally, the EPSs with AMWs>14kDa had stronger binding capability with Cu(II) than EPSs with AMWs of 1-14kDa. The difference in Cu binding behavior of LBEPS and TBEPS significantly affect the mobility, bioavailability, and toxicity of Cu in aquatic environments. ? 2011 Taiwan Institute of Chemical Engineers. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/407738 | ISSN: | 18761070 | DOI: | 10.1016/j.jtice.2011.12.010 |
顯示於: | 化學工程學系 |
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