title: Effective methods for extracting extracellular polymeric substances from Shewanella oneidensis MR-1.
abstract: Extracellular polymeric substances (EPS) play crucial roles in bio-aggregate formation and survival of bacterial cells. To develop an effective but harmless method for EPS extraction from Shewanella oneidensis MR-1, five extraction methods, i.e. centrifugation (control), heating (40, 45, 50, and 60 °C), and treatments with H2SO4, ethylenediaminetetraacetic acid (EDTA) and NaOH, were examined, respectively. Results from scanning electron microscope and flow cytometric analyses indicate that MR-1 cells were severely broken by H2SO4, NaOH and heating temperature ≥45 °C. Proteins and polysaccharides in EPS extracted by heating at 40 °C were 7.12 and 1.60 mg g-1dry cell, respectively. Although EDTA treatment had a relatively lower yield of EPS (proteins and polysaccharides yields of 5.15 and 1.30 mg g-1dry cell, respectively), cell lysis was barely found after EPS extraction. Three peaks were identified from the three-dimensional excitation-emission matrix spectrum of each EPS sample, suggesting the presence of protein-like substances. Furthermore, the peak intensity was in good accordance with protein concentration measured by the chemical analysis. In short, heating (40 °C) and EDTA treatments were found the most suitable methods for EPS extraction considering the cell lysis and EPS content, composition and functional groups together.
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn; College of Life Sciences, Fujian Normal University, Fuzhou 350108, China.
authors.forename: You-Fen
authors.initials: YF
authors.lastname: Dai
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn.
authors.forename: En-Hua
authors.initials: EH
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn; College of Life Sciences, Fujian Normal University, Fuzhou 350108, China.
authors.forename: Li-Dan
authors.initials: LD
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Qiu
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn.
authors.forename: Le-Xing
authors.initials: LX
authors.lastname: You
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn.
authors.forename: Gurumurthy
authors.initials: G
authors.lastname: Dummi Mahadevan
authors.affiliation: College of Life Sciences, Fujian Normal University, Fuzhou 350108, China.
authors.forename: Bi-Lian
authors.initials: BL
authors.lastname: Chen
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
mesh_terms: D001704:Biopolymers / Q000302:isolation & purification*; D005591:Chemical Fractionation / Q000379:methods*; D005434:Flow Cytometry; D008855:Microscopy, Electron, Scanning; D011108:Polymers / Q000737:chemistry; D011134:Polysaccharides / Q000302:isolation & purification*; D011506:Proteins / Q000302:isolation & purification*; D020592:Shewanella / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001704:Biopolymers; D011108:Polymers; D011134:Polysaccharides; D011506:Proteins