Adsorption behavior of tightly bound extracellular polymeric substances on model organic surfaces under different pH and cations with surface plasmon resonance

Tightly bound extracellular polymeric substances (TB-EPS) play a substantial role on microbial aggregates, which can promote microbial cells to aggregate and adhere onto the carrier in bioreactor. However, the attachment and adsorption of TB-EPS on different surfaces were awaited to be elucidated. In this study, four self-assembled monolayers (SAMs) carrying methyl (CH3-SAM), amino (NH2-SAM), hydroxyl (OH-SAM), and carboxyl (COOH-SAM) terminal groups were prepared to model different surfaces. TB-EPS adsorption on these surfaces under different pH conditions and additional cations were investigated using surface plasmon resonance. The adsorption of TB-EPS dramatically decreased with the decreasing pH values. CH3-SAM surface achieved the maximum adsorption at the same condition. Na(+) promoted the TB-EPS adsorbed on COOH-SAM surface. The Ca(2+)-mediated complexes were attracted by COOH-SAM and repelled by NH2-SAM, respectively. The adsorptions of TB-EPS on the four SAM surfaces were significantly increased by adding Fe(3+). These results demonstrated that the TB-EPS adsorption on the organic surfaces were dependent on the pH and cation of solution.

Publication year: 2014
Authors: Zhang P. 1, Chen Y.P. 2, Guo J.S. 3, Shen Y. 4, Yang J.X. 4, Fang F. 1, Li C. 1, Gao X. 1, Wang G.X. 5
Affiliations:

1 – Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
2 – Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
3 – Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
4 – Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
5 – College of Bioengineering, Chongqing University, Chongqing 400045, China

Published in: Water Research, 2014, Vol.57, p. 31-9
DOI: 10.1016/j.watres.2014.03.018

MP-SPR KEYWORDS

adsorption COOH) different pH extracellular polymeric substances (protein) humic acids NH2 OH on different SAM surfaces (CH3 polysaccharides

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