Abstract 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.
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.
- Content Type Journal Article
- DOI 10.1007/s10811-009-9488-8
- Authors
- Dries Vandamme, K.U.Leuven Campus Kortrijk Laboratory Aquatic Biology E. Sabbelaan 53 8500 Kortrijk Belgium
- Imogen Foubert, K.U.Leuven Campus Kortrijk Laboratory Aquatic Biology E. Sabbelaan 53 8500 Kortrijk Belgium
- Boudewijn Meesschaert, Katholieke Hogeschool Brugge-Oostende Department of Industrial Sciences and Technology Zeedijk 101 8400 Oostende Belgium
- Koenraad Muylaert, K.U.Leuven Campus Kortrijk Laboratory Aquatic Biology E. Sabbelaan 53 8500 Kortrijk Belgium
- Journal Journal of Applied Phycology
- Online ISSN 1573-5176
- Print ISSN 0921-8971
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