title: Effective harvesting of microalgae: Comparison of different polymeric flocculants.
abstract: Microalgae harvesting is a major hurdle in the use of microalgae for oil production. Here we describe the use of a standard cationic polymer used for water treatment, Polydiallyldimethylammonium chloride (PDADMAC), for sedimentation of Chlorella vulgaris and comparison of its flocculation properties with two other polymers, chitosan and Superfloc®. We found PDADMAC to be the most effective flocculant with 90% of the algae flocculating at concentrations as low as 5mg/L within 60min, and good activity even at pH=10. Interestingly, with both PDADMAC and chitosan maximum flocculation was achieved much before zeroing of zeta potential. PDADMAC flocculation was also very effective in enhancing harvest by filtration and somewhat at flocculation and sedimentation of marine algae, Nannochloropsis salina.
authors.affiliation: Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa-Oranim, Tivon 3600600, Israel. Electronic address: gerchman.yoram@gmail.com.
authors.forename: Yoram
authors.initials: Y
authors.lastname: Gerchman
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Barak
authors.initials: B
authors.lastname: Vasker
authors.affiliation: Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa-Oranim, Tivon 3600600, Israel.
authors.forename: Mordechai
authors.initials: M
authors.lastname: Tavasi
authors.affiliation: Department of Soil and Water Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Mishael
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Kinel-Tahan
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Yehoshua
mesh_terms: D018533:Biomass; D018929:Cell Culture Techniques / Q000379:methods*; D048408:Chlorella vulgaris / Q000187:drug effects / Q000254:growth & development*; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D058086:Microalgae / Q000187:drug effects / Q000254:growth & development*; D011108:Polymers / Q000494:pharmacology*; D012623:Seawater / Q000382:microbiology; D055672:Static Electricity; D014867:Water
chemical_list: D011108:Polymers; D014867:Water
keywords: Biofuels; Filtration; Harvesting; Microalgae; Polymer; Sedimentation; Water reuse