Biosorption of Cu（II） to extracellular polymeric substances （EPS） from Synechoeystis sp.： a fluorescence quenching study

作     者：Xiangliang PAN Jing LIU Wenjuan SONG Daoyong ZHANG 

作者机构：State Key Laboratory of Desert and Oasis EcologyXinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China State Key Laboratory of Environmental GeochemistryInstitute of GeochemistryChinese Academy of SciencesGuiyang 550002China 

出 版 物：《Frontiers of Environmental Science & Engineering》 (环境科学与工程前沿（英文）)

年 卷 期：2012年第6卷第4期

页      面：493-497页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070302[理学-分析化学] 0703[理学-化学] 0713[理学-生态学] 

基　　金：This work was supported by Program of 100 Distinguished Young Scientists of the Chinese Academy of Sciences and National Natural Science Foundation of China (Grant Nos. Ul120302 and 21177127) 

主　　题：biosorption conditional binding constant extracellular polymeric substances (EPS) fluorescence quenching 

摘      要：Biosorption of extracellular polymeric substances （EPS） from Synechocystis sp. （cyanobacterium） with Cu（II） was investigated using fluorescence spectroscopy. Three fluorescence peaks were found in the excitation-emission matrix （EEM） fluorescence spectra of EPS. Fluorescence of peak A （Ex/Em = 275/452 nm） and peak C （Ex/Em= 350/452nm） were originated from humic-like substances and fluorescence of peak B （Ex/ Em= 275/338nm） was attributed to protein-like sub- stances. Fluorescence of peaks A, B, and C could be quenched by Cu（II）. The effective quenching constants （lg Ka） were 2.8-5.84 for peak A, 6.4-9.24 for peak B, and 3.48-6.68 for peak C, respectively. The values of lg Ka showed a decreasing trend with increasing temperature, indicating that the quenching processes were static in nature. The binding constants （lg Kb） followed the order of peak A 〉 peak B 〉 peak C, implying that the humic-like substances in EPS have greater Cu（II） binding capacity than the protein-like substances. The binding site number, n, in EPS-Cu（II） complexes for peaks A, B, and C was less than 1. This suggests the negative cooperativity between multiple binding sites and the presence of more than one Cu binding site.