title: Influence of extracellular polymeric substances (EPS) on Cd adsorption by bacteria.
abstract: The role of extracellular polymeric substances (EPS) in Cd adsorption by Bacillus subtilis and Pseudomonas putida was investigated using a combination of batch adsorption experiments, potentiometric titrations, Fourier transform infrared spectroscopy (FTIR). An increased adsorption capacity of Cd was observed for untreated bacteria relative to that for EPS-free bacteria. Surface complexation modeling of titration data showed the similar pKa values of functional groups (carboxyl, phosphate and hydroxyl) between untreated and EPS-free bacteria. However, site concentrations on the untreated bacteria were found to be higher than those on the EPS-free bacteria. FTIR spectra also showed that no significant difference in peak positions was observed between untreated and EPS-free bacteria and carboxyl and phosphate groups were responsible for Cd adsorption on bacterial cells. The information obtained in this study is of fundamental significance for understanding the interaction mechanisms between heavy metals and biofilms in natural environments.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Wei
authors.forename: Linchuan
authors.initials: L
authors.lastname: Fang
authors.forename: Peng
authors.initials: P
authors.lastname: Cai
authors.forename: Qiaoyun
authors.initials: Q
authors.lastname: Huang
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
authors.forename: Xinming
authors.initials: X
authors.lastname: Rong
mesh_terms: D000327:Adsorption; D001412:Bacillus subtilis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D002104:Cadmium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D011199:Potentiometry; D016958:Pseudomonas putida / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001426:Bacterial Proteins; D011108:Polymers; D011135:Polysaccharides, Bacterial; D002104:Cadmium