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Kortrijk, Belgium

Sabbe K.,Ghent University | Vanelslander B.,Ghent University | Ribeiro L.,University of Lisbon | Witkowski A.,University Of Szczecin | And 2 more authors.
Vie et Milieu | Year: 2010

A new, monospecific diatom genus, Pierrecomperia gen. nov. (typus generis P. catenuloides), is described. In addition, a new species is described in the genus Cymatosira Grunow, viz. C. minutissima. We also propose two new combinations in the genus Plagiogrammopsis Hasle, von Stosch & Syvertsen, namely P. minima comb. nov. and P. sigmoidea comb, nov. (both formerly placed in Plagiogramma Greville). Plagiogramma parallelum Salah, P. minimum Salah and P. sigmoideum Salah are lectotypified. P. parallelum is synonymized with Brockmanniella brockmannii (Hustedt) Hasle, von Stosch & Syvertsen. Morphological and molecular (18S rDNA and rbcL) evidence firmly places Pierrecomperia in the centric diatom family Cymatosiraceae, which is uniquely characterized by the presence of ocelluli. Like Extubocellulus and Pseudoleyanella, Pierrecomperia is isovalvar and is therefore placed in the subfamily Extubocelluloideae. Like most members of the diatom family Cymatosiraceae, the above-mentioned taxa are confined to coastal shallow water habitats where they have adopted a benthic or tychoplanktonic life-form. Their biogeography and autecology is discussed. Source

Ryckebosch E.,U-Systems | Muylaert K.,Laboratory Aquatic Biology | Foubert I.,U-Systems
JAOCS, Journal of the American Oil Chemists' Society | Year: 2012

An optimized procedure for extraction of total and non-polar lipids from microalgae is proposed. The effects of solvent, pretreatment (lyophilization, inactivation of lipases, and addition of antioxidants) and cell-disruption (liquid nitrogen, sonication, and bead beating) on total lipid content, lipid class, and fatty acid composition were examined. Chloroform-methanol 1:1 was shown to be the best solvent mixture for extraction of total lipids from microalgae. When performing this extraction, lyophilized algae can be used, no pretreatment with isopropanol to inactivate the lipases is needed and addition of antioxidants is not necessary. Furthermore, cell-disruption is not essential, although in that case two extractions must be performed in series to ensure that, irrespective of the microalgal species, all lipids are extracted. Determination of non-polar lipid content should be performed by separation of the total lipid extract on an SPE column. Extraction using petroleum ether is only appropriate when a bead beater is used for pretreatment. © AOCS 2011. Source

Vandamme D.,Laboratory Aquatic Biology | Foubert I.,Laboratory Aquatic Biology | Fraeye I.,Laboratory Aquatic Biology | Meesschaert B.,Catholic University College of Bruges-Ostend | And 2 more authors.
Bioresource Technology | Year: 2012

Microalgae hold great potential as a feedstock for biofuels or bulk protein or treatment of wastewater or flue gas. Realising these applications will require the development of a cost-efficient harvesting technology. Here, we explore the potential of flocculation induced by high pH for harvesting Chlorella vulgaris. Our results demonstrate that flocculation can be induced by increasing medium pH to 11. Although both calcium and magnesium precipitated when pH was increased, only magnesium (≥0.15. mM) proved to be essential to induce flocculation. The costs of four different bases (sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and sodium carbonate) were calculated and evaluated and the use of lime appeared to be the most cost-efficient. Flocculation induced by high pH is therefore a potentially useful method to preconcentrate freshwater microalgal biomass during harvesting. © 2011 Elsevier Ltd. Source

Vandamme D.,Laboratory Aquatic Biology | Foubert I.,Laboratory Aquatic Biology | Meesschaert B.,Catholic University College of Bruges-Ostend | Meesschaert B.,Catholic University of Leuven | Muylaert K.,Laboratory Aquatic Biology
Journal of Applied Phycology | Year: 2010

Due to their small size and low concentration in the culture medium, cost-efficient harvesting of microalgae is a major challenge. We evaluated the potential of cationic starch as a flocculant for harvesting microalgae using jar test experiments. Cationic starch was an efficient flocculant for freshwater (Parachlorella, Scenedesmus) but not for marine microalgae (Phaeodactylum, Nannochloropsis). At high cationic starch doses, dispersion restabilization was observed. The required cationic starch dose to induce flocculation increased linearly with the initial algal biomass concentration. Of the two commercial cationic starch flocculants tested, Greenfloc 120 (used in wastewater treatment) was more efficient than Cargill C*Bond HR 35.849 (used in paper manufacturing). For flocculation of Parachlorella using Greenfloc 120, the cationic starch to algal biomass ratio required to flocculate 80% of algal biomass was 0.1. For Scenedesmus, a lower dose was required (ratio 0.03). Flocculation of Parachlorella using Greenfloc 120 was independent of pH in the pH range of 5 to 10. Measurements of the maximum quantum yield of PSII suggest that Greenfloc 120 cationic starch was not toxic to Parachlorella. Cationic starch may be used as an efficient, nontoxic, cost-effective, and widely available flocculant for harvesting microalgal biomass. © 2009 Springer Science+Business Media B.V. Source

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