title: Further examination of polysaccharides causing membrane fouling in membrane bioreactors (MBRs): Application of lectin affinity chromatography and MALDI-TOF/MS.
abstract: Membrane fouling remains a major obstacle for wider application of membrane bioreactors (MBRs) to wastewater treatment. Polysaccharides in mixed liquor suspensions in the reactors are thought to be mainly responsible for the evolution of membrane fouling in MBRs. However, details of polysaccharides causing membrane fouling in MBRs are still unknown. In this study, polysaccharides in a mixed liquor suspension of a pilot-scale MBR treating municipal wastewater were fractionated by using lectins, special proteins that bind to specific polysaccharides depending on their properties. Fouling potentials of the fractionated polysaccharides were assessed by bench-scale dead-end filtration tests. It was clearly shown that the degrees of fouling caused by fractionated polysaccharides were significantly different. The amounts of polysaccharides in each fraction could not explain the variations in the fouling, indicating the presence of polysaccharides with high specific fouling potentials. To investigate structures and origins of the polysaccharides with high fouling potentials, matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF)/mass spectrometry (MS) analysis was applied to the fractionated polysaccharides after partial hydrolysis. Several mass peaks obtained could be assigned to fragments of structures of polysaccharides (i.e., oligosaccharides) reported in a database/literature. This is the first report showing the plausible structures of polysaccharides in MBRs based on MS. A deeper understanding and effective control of membrane fouling in MBRs could be achieved with information obtained by the approach used in this study.
authors.affiliation: Division of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan. Electronic address: kkatsu@eng.hokudai.ac.jp.
authors.forename: Katsuki
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Division of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
authors.forename: Ippei
authors.initials: I
authors.lastname: Tanaka
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo 001-0012, Japan.
authors.forename: Shin-Ichiro
authors.initials: SI
authors.lastname: Nishimura
authors.affiliation: Medicinal Chemistry Pharmaceuticals, LLC, 1-715, N7W4, Kita-ku, Sapporo 060-0807, Japan.
authors.forename: Risho
authors.initials: R
authors.lastname: Miyoshi
authors.affiliation: Center for Environmental Nano and Bio Engineering, Hokkaido University, Sapporo 060-8628, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Miyoshi
authors.affiliation: Center for Environmental Nano and Bio Engineering, Hokkaido University, Sapporo 060-8628, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D002846:Chromatography, Affinity; D008567:Membranes, Artificial; D011134:Polysaccharides / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D008567:Membranes, Artificial; D011134:Polysaccharides