Ratio between autoflocculating and target microalgae affects the energy-efficient harvesting by bio-flocculation.

The effect of ratio between autoflocculating and target microalgae in bio-flocculation was studied with emphasis on the recovery, sedimentation rate and energy demand for harvesting the target microalgae. When the autoflocculating microalgae Ettlia texensis, Ankistrodesmus falcatus and Scenedesmus obliquus were added to Chlorella vulgaris at a ratio of 0.25, the recovery of C. vulgaris increased from 25% to, respectively, 40%, 36% and 31%. The sedimentation rate increased as well. Addition of Tetraselmis suecica to Neochloris oleoabundans at a ratio of 0.25 increased the recovery from 40% to 50%. Application of bio-flocculation at a ratio of 0.25, followed by centrifugation reduces the energy demand for harvesting of the target microalgae from 13.8 MJ kgDW(-1) if only centrifugation is used to 1.83, 1.81, 1.53 and 1.34 MJ kgDW(-1), respectively, using T. suecica, E. texensis, A. falcatus and S. obliquus and 3h sedimentation before centrifugation.

[1]  Maria J Barbosa,et al.  Microalgal production--a close look at the economics. , 2011, Biotechnology advances.

[2]  Y. Chisti,et al.  Recovery of microalgal biomass and metabolites: process options and economics. , 2003, Biotechnology advances.

[3]  R. Sims,et al.  Production and harvesting of microalgae for wastewater treatment, biofuels, and bioproducts. , 2011, Biotechnology advances.

[4]  McGarry Mg.  Algal flocculation with aluminum sulfate and polyelectrolytes. , 1970 .

[5]  Aikaterini Papazi,et al.  Harvesting Chlorella minutissima using cell coagulants , 2010, Journal of Applied Phycology.

[6]  Hongli Zheng,et al.  Harvesting of microalgae by flocculation with poly (γ-glutamic acid). , 2012, Bioresource technology.

[7]  Imogen Foubert,et al.  Evaluation of electro‐coagulation–flocculation for harvesting marine and freshwater microalgae , 2011, Biotechnology and bioengineering.

[8]  D. Vandamme,et al.  Flocculation of Chlorella vulgaris induced by high pH: role of magnesium and calcium and practical implications. , 2012, Bioresource technology.

[9]  Yoon,et al.  Effects of harvesting method and growth stage on the flocculation of the green alga Botryococcus braunii , 1998 .

[10]  R. Wijffels,et al.  An Outlook on Microalgal Biofuels , 2010, Science.

[11]  G. Shelef,et al.  Microalgae harvesting and processing: a literature review , 1984 .

[12]  C. Posten,et al.  Second Generation Biofuels: High-Efficiency Microalgae for Biodiesel Production , 2008, BioEnergy Research.

[13]  Zechen Wu,et al.  Evaluation of flocculation induced by pH increase for harvesting microalgae and reuse of flocculated medium. , 2012, Bioresource technology.

[14]  S. Einbinder,et al.  Inexpensive non-toxic flocculation of microalgae contradicts theories; overcoming a major hurdle to bulk algal production. , 2012, Biotechnology advances.

[15]  Andrew Hoadley,et al.  Dewatering of microalgal cultures : a major bottleneck to algae-based fuels , 2010 .

[16]  Peter J. Ashman,et al.  Microbial flocculation, a potentially low-cost harvesting technique for marine microalgae for the production of biodiesel , 2009, Journal of Applied Phycology.

[17]  René H. Wijffels,et al.  Harvesting of microalgae by bio-flocculation , 2010, Journal of Applied Phycology.