title: Characterisation of algal organic matter produced by bloom-forming marine and freshwater algae.
abstract: Algal blooms can seriously affect the operation of water treatment processes including low pressure (micro- and ultra-filtration) and high pressure (nanofiltration and reverse osmosis) membranes mainly due to accumulation of algal-derived organic matter (AOM). In this study, the different components of AOM extracted from three common species of bloom-forming algae (Alexandrium tamarense, Chaetoceros affinis and Microcystis sp.) were characterised employing various analytical techniques, such as liquid chromatography - organic carbon detection, fluorescence spectroscopy, fourier transform infrared spectroscopy, alcian blue staining and lectin staining coupled with laser scanning microscopy to indentify its composition and force measurement using atomic force microscopy to measure its stickiness. Batch culture monitoring of the three algal species illustrated varying characteristics in terms of growth pattern, cell concentration and AOM release. The AOM produced by the three algal species comprised mainly biopolymers (e.g., polysaccharides and proteins) but some refractory compounds (e.g., humic-like substances) and other low molecular weight acid and neutral compounds were also found. Biopolymers containing fucose and sulphated functional groups were found in all AOM samples while the presence of other functional groups varied between different species. A large majority (>80%) of the acidic polysaccharide components (in terms of transparent exopolymer particles) were found in the colloidal size range (<0.4 μm). The relative stickiness of AOM substantially varied between algal species and that the cohesion between AOM-coated surfaces was much stronger than the adhesion of AOM on AOM-free surfaces. Overall, the composition as well as the physico-chemical characteristics (e.g., stickiness) of AOM will likely dictate the severity of fouling in membrane systems during algal blooms.
authors: UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, Netherlands; Wetsus Center of Excellence for Sustainable Water Technology, Agora 1, 8934 CJ Leeuwarden, Netherlands. Electronic address: l.villacorte@unesco-ihe.org.
authors: L O
authors: LO
authors: Villacorte
authors: UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, Netherlands.
authors: Y
authors: Y
authors: Ekowati
authors: Department of River Ecology, Helmholtz Centre for Environmental Research (UFZ), Brueckstrasse 3A, 39114 Magdeburg, Germany.
authors: T R
authors: TR
authors: Neu
authors: Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703HB Wageningen, Netherlands.
authors: J M
authors: JM
authors: Kleijn
authors: Water Desalination and Reuse Center, King Abdullah University of Science and Technology, 4700 KAUST, Thuwal, Saudi Arabia; Fairleigh Dickinson University, Teaneck, NJ 07666, USA.
authors: H
authors: H
authors: Winters
authors: UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, Netherlands; Water Desalination and Reuse Center, King Abdullah University of Science and Technology, 4700 KAUST, Thuwal, Saudi Arabia; Delft University of Technology, Stevinweg 1, 2628 CN Delft, Netherlands.
authors: G
authors: G
authors: Amy
authors: UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, Netherlands.
authors: J C
authors: JC
authors: Schippers
authors: UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, Netherlands; Delft University of Technology, Stevinweg 1, 2628 CN Delft, Netherlands.
authors: M D
authors: MD
authors: Kennedy
mesh_terms: D017377:Diatoms / Q000378:metabolism*; D004141:Dinoflagellida / Q000378:metabolism*; D005068:Eutrophication; D046931:Microcystis / Q000378:metabolism*; D009930:Organic Chemicals / Q000032:analysis
chemical_list: D009930:Organic Chemicals
keywords: Atomic force microscopy (AFM); Cyanobacteria; Diatoms; Dinoflagellates; Fluorescence excitation emission matrix (FEEM); Lectin staining coupled with confocal laser scanning microscopy (CLSM)