title: Interactions of EPS with soil minerals: A combination study by ITC and CLSM.
abstract: The adsorption of extracellular polymeric substances (EPS) from Pseudomonas putida on montmorillonite, kaolinite and goethite was investigated as a function of pH using batch studies coupled with confocal laser scanning microscopy (CLSM) and isothermal titration calorimetry (ITC). Characterization by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy showed that the extracted EPS contained carboxyl, phosphoryl, amino, and hydroxyl on functional groups as well as polysaccharides, protein and nucleic acid on components. The mass fraction of EPS adsorption on minerals decreased with the final pH increased from 3.0 to 9.0. The mass fraction of EPS-N adsorption varied with pH values and was higher than that of EPS-C or EPS-P on montmorillonite and kaolinite, while the mass fraction of EPS-P adsorption was the highest on goethite. CLSM results further demonstrated that proteins were predominantly distributed on the montmorillonite and kaolinite surfaces, while nucleic acids were mainly on the goethite surface. ITC results revealed that the adsorption process in all mineral systems was exothermic, and pH altered the heat effect of EPS-mineral reactions. The data obtained in this study would facilitate a better understanding of the adsorption mechanisms of EPS on minerals.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Di
authors.initials: D
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Wenting
authors.initials: W
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yixuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Qiaoyun
authors.initials: Q
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: cp@mail.hzau.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Cai
mesh_terms: D000327:Adsorption; D000465:Algorithms; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001546:Bentonite / Q000737:chemistry; D002151:Calorimetry / Q000379:methods*; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000737:chemistry; D007616:Kaolin / Q000737:chemistry; D018613:Microscopy, Confocal / Q000379:methods*; D008903:Minerals / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D016958:Pseudomonas putida / Q000378:metabolism; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D058085:Iron Compounds; D008903:Minerals; D011108:Polymers; D011134:Polysaccharides; D012329:RNA, Bacterial; D012987:Soil; D001546:Bentonite; C094886:goethite; D007616:Kaolin
keywords: Adsorption; CLSM; EPS; ITC; Mineral