Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Effect of substrate feeding on viscosity evolution of anaerobic granular sludges
Pevere, A. ; Abzac, P. D'; Hullebusch, E. ; Lens, P.N.L. ; Guibaud, G. - \ 2010
Water Science and Technology 62 (2010)1. - ISSN 0273-1223 - p. 132 - 139.
polymeric substances - rheological characterization - extracellular polymers - activated-sludge - uasb reactors - waste-water - wastewaters - extraction - dynamics - biofilms
This work aims to describe the effect of the feeding regime of anaerobic activity tests on the limit viscosity (mu(lim)) evolution of the granules. Batch experiments were performed with 3 different sources of substrate: acetate, peptone, and glucose. Despite, the substrate origin was shown to affect the mu(lim) evolution of granules, no clear relationship was found between the mu(lim) evolution, type of substrate and other granule physico-chemical characteristics (i.e. pH; % of Volatile Suspended Solid; concentration of exopolymeric substances, divalent cations, P and S). The origin of granules and the substrate feeding regime modify the surface shape of the granules and may change granule-granule interactions under a shear stress, thus affecting the evolution of the v value during long term reactor operation.
Extraction of extracellular polymeric substances (EPS) from anaerobic granular sludges: comparison of chemical and physical extraction protocols
Abzac, P. D'; Bordas, F. ; Hullebusch, E. ; Lens, P.N.L. ; Guibaud, G. - \ 2010
Applied Microbiology and Biotechnology 85 (2010)5. - ISSN 0175-7598 - p. 1589 - 1599.
activated-sludge - waste-water - polysaccharides - complexation - flocs - acid
The characteristics of the extracellular polymeric substances (EPS) extracted with nine different extraction protocols from four different types of anaerobic granular sludge were studied. The efficiency of four physical (sonication, heating, cationic exchange resin (CER), and CER associated with sonication) and four chemical (ethylenediaminetetraacetic acid, ethanol, formaldehyde combined with heating, or NaOH) EPS extraction methods was compared to a control extraction protocols (i.e., centrifugation). The nucleic acid content and the protein/polysaccharide ratio of the EPS extracted show that the extraction does not induce abnormal cellular lysis. Chemical extraction protocols give the highest EPS extraction yields (calculated by the mass ratio between sludges and EPS dry weight (DW)). Infrared analyses as well as an extraction yield over 100% or organic carbon content over 1 g g(-1) of DW revealed, nevertheless, a carry-over of the chemical extractants into the EPS extracts. The EPS of the anaerobic granular sludges investigated are predominantly composed of humic-like substances, proteins, and polysaccharides. The EPS content in each biochemical compound varies depending on the sludge type and extraction technique used. Some extraction techniques lead to a slightly preferential extraction of some EPS compounds, e.g., CER gives a higher protein yield.
Effects of extraction procedures on metal binding properties of extracellular polymeric substances (EPS) from anaerobic granular sludges
Abzac, P. D'; Bordas, F. ; Hullebusch, E. ; Lens, P.N.L. ; Guibaud, G. - \ 2010
Colloids and Surfaces. B: Biointerfaces 80 (2010)2. - ISSN 0927-7765 - p. 161 - 168.
activated-sludge - titration data - biosorption - cadmium - complexation - adsorption - sorption - lead - cd - constants
The effects of the extraction procedure of extracellular polymeric substances (EPS) on their proton/metal binding properties were studied. Nine extraction procedures (one control, four physical and four chemical procedures) were applied to four types of anaerobic granular sludges. The binding capacities between the EPS and lead or cadmium were investigated at pH 7 by a polarographic method. The composition of the EPS extracts varied according to the extraction technique and the origin of the sludge. This induced differences in the pK(a)s and the binding sites density of the EPS extracts. The carry-over of the extractant in the samples strongly affects the properties of the EPS from chemical extraction protocols. Lead and cadmium seem to be bound differently with the EPS, a higher binding capacity was observed for Pb2+ than for Cd2+.
Characterization of the Mineral Fraction Associated to Extracellular Polymeric Substances (EPS) in Anaerobic Granular Sludges
Abzac, P. D'; Bordas, F. ; Joussein, E. ; Hullebusch, E. ; Lens, P.N.L. ; Guibaud, G. - \ 2010
Environmental Science and Technology 44 (2010)1. - ISSN 0013-936X - p. 412 - 418.
waste-water - extraction methods - heavy-metals - part i - removal - sulfate - reactor - mechanisms - dynamics - sorption
The extracellular polymeric substances (EPS) extracted from four anaerobic granular sludges contain an important mineral fraction (20-77% of the EPS dry weight). The composition of the mineral fraction of EPS depends strongly of the extraction method applied and to a lesser extend of the origin of the anaerobic sludge. Centrifugation, sonication, and heating extraction procedures yield a similar mineral composition. However, extraction using a cationic exchange resin (CER) leads to an increase of the Na+ content in the EPS extract because the CER promotes an exchange of divalent and trivalent inorganic elements in the EPS extracts toward Na+. Chemical extraction protocols were also shown to contaminate the EPS extracts by impurities or carry over of the extractant itself (e.g., ethanol). A part of the mineral fraction is bound to the EPS organic matter and structures the EPS matrix in the granules. Scanning electron microscopic analysis (SEM-EDX) showed that in addition, solid particles such as CaCO3 and Ca5OH(PO4)(3) containing various metallic elements (i.e., Al, Fe, Cu, Mn...) are present in the EPS as well. This inorganic fraction, too often neglected in EPS studies, can influence the physicochemical properties of EPS.
Evaluation of size exclusion chromatography (SEC) for the characterization of extracellular polymeric substances (EPS) in anaerobic granular sludges
Simon, S. ; Pairo, B. ; Villain, M. ; Abzac, P. D'; Hullebusch, E. ; Lens, P.N.L. ; Guibaud, G. - \ 2009
Bioresource Technology 100 (2009)24. - ISSN 0960-8524 - p. 6258 - 6268.
activated-sludge - extraction methods - part i - exopolymers - biofilms - polysaccharides - complexation - separation - protocols - hplc
The extracellular polymeric substances (EPS) extracted from three granular and one flocculant anaerobic sludges were characterised by size exclusion chromatography (SEC) using two serially linked chromatographic columns in order to obtain more detailed chromatograms. A Superdex peptide 10/300 GL (0.1-7 kDa) and Superdex 20010/300GL (10-600 kDa) from Amersham Biosciences were used in series with a mobile phase at pH 7 with an ionic strength of 0.223 M (phosphate buffer 50 mM and NaCl 150 mM). A part of the EPS molecules displays hydrophobic and/or ionic interactions with the column packing. Interactions could be modified by changing the mobile phase ionic strength or polarity (addition of acetonitrile). The detection wavelength (210 or 280 nm) affects strongly the EPS chromatogram. For a sludge originating from the same type of biofilms (i.e., anaerobic granules), the differences in EPS fingerprints are mainly due to differences in the absorbance of the chromatographic peaks, linked to EPS molecules content and composition. The EPS fingerprint changes significantly when the EPS originate from another type of anaerobic sludges. In addition, EPS fingerprints were affected by the extraction method used (centrifugation only; heat and centrifugation or cationic exchange resin and centrifugation). This phenomenon was observed mainly for the largest and smallest molecules and molecules which display interactions with column packing.
Fate and forms of Cu in a reservoir ecosystem following copper sulfate treatment
Hullebusch, E. ; Chatenet, P. ; Deluchat, V. ; Chazal, P.M. ; Froissard, D. ; Lens, P.N.L. ; Baudu, M. - \ 2003
Journal de Physique IV France 107 (2003). - ISSN 1155-4339 - p. 1333 - 1336.
successive chemical treatments - shallow eutrophied lake - environmental-impact - sediments
Copper sulfate (CuSO4) addition to freshwater for phytoplankton control has been practiced for decades, and remains the most effective algicidal treatment for numerous managed water bodies. A reservoir in the centre of France was the site for an investigation of copper distribution in aquatic systems after a copper sulfate treatment Results of copper monitoring showed a rapid conversion of dissolved Cu to particulate forms, with significant accumulation in the sediments(83% of total copper added). Total sediment Cu content increased from approximately 37.7 to 45.4 mug.g(-1) dry weight after the first treatment. Sequential extraction suggested that a significant portion of the sediment-borne Cu was associated with the organic fraction which may release Cu to the water column, although significant release would occur only under extreme changes in water chemistry. Based upon measured Cu concentrations, flows at the down-stream water, and known mass applied during treatment, mass balance calculations indicated that approximately 17% of the Cu was exported from the reservoir over a 70 day period following a 196 mug.L-1 Cu2+ (as CuSO4, 5 H2O) treatment. The largest amount of copper was probably adsorbed on downstream sediment or lost in running water. Copper bioaccumulation by a moss, Fontinalis antipyretica, in the down-stream water showed that it was possible to distinguish between a treated and an untreated area. The impact of copper treatment in the down-stream reservoir could be followed using mosses. The bioaccumulation data further showed that there is a distance effect which could be exploited to determine potential copper impact on receiving water bodies. Thirty days after copper sulfate addition, Fontinalis still indicated copper exposure.
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