Harvesting of Microalgae Dunaliella salina Using Electroflocculation

Authors
A. Zenouzi 1
B. Ghobadian 1
M. A. Hejazi 2
P. Rahnemoon 3
1 Department of Agricultural Machinery, Faculty of Agriculture, Tarbiyat Modares University, Tehran, Islamic Republic of Iran.
2 Agricultural Biotechnology Research Institute of Iran, Branch for North West and West, Tabriz, Islamic Republic of Iran.
3 Department of Food Science and Technology, Faculty of Agriculture, Tabriz University. Tabriz, Islamic Republic of Iran.
Abstract
One of the important bottle-necks in production of microalgae based biodiesel is the lack of an efficient method for harvesting of microalgae from the culture medium. In this study, the electroflocculation method was developed for harvesting of microalgae Dunaliella cells from culture medium. The effect of several parameters such as the current density, electrical conductivity of culture medium, time, electrode gap, and electrode type on harvesting efficiency and energy consumption were also determined. The maximum harvesting efficiency of this method was 97.44% at EC= 1.35 S m-1 and current density of 90 A m-2 during 3 minutes electroflocculation process in a 300 ml beaker. The maximum efficiency was achieved by aluminum electrodes with 1 cm distance between electrodes and the maximum energy consumption for this practice was 0.621 kW h m-3. It was concluded that electroflocculation is an efficient and cost effective method for microalgae harvesting.

Keywords

1. Chisti, Y. 2007. Biodiesel from Microalgae. Biotechnol. Advan., 25: 294–306.
2. Danquah, M. K., Ang, L., Uduman, N., Moheimani, N. and Forde, G. M. 2008. Dewatering of Microalgal Culture for Biodiesel Production: Exploring Polymer Flocculation and Tangentional Flow Filtration. J. Chem. Technol. Biotechnol., 84:1078-1083.
3. Dote, Y., Sawayama, S., Inoue, S., Minowa, T. and Yokoyama, S. 1994. Recovery of Liquid Fuel from Hydrocarbon-rich Microalgae by Thermochemical Liquefaction. Fuel, 73: 1855–1857.
4. Harith, T. H., Yuosoff, F. M., Mohemed, M. S., Mohemed Din, M. S. and Ariff, A. B. 2009. Effect of Different Flocculants on the Flocculation Performance of Mcroalgae, Chaetoceros Calcitrans, Cells. African J. Biotechnol., 8(21): 5971-5978.
5. Horiuchi, J., Ohba, I., Tada, K., Kobayashi, M., Kanno, T. and Kishimoto, M. 2003. Effective Cell Harvesting of the Halotolerant Microalga Dunaliella with pH Control. J. Biosci. Bioengineer., 95(4): 412-415, 2003.
6. Knuckey, R., Brown, M., Robert, R. and Frampton, D. 2006 Production of Microalgal Concentrates by Flocculation and Their Assessment as Aquaculture Feeds. Aquacul. Engin., 35: 300–313.
7. Levin, G. V., Clendenninig, J. R., Gibor, A. and Bogar, F. D. 1962. Harvesting of Algae by Froth Flotation. Resource Research Ins., Washington, PP. 169-174.
8. Minowa, T., Yokoyama, S. Y., Kishimoto, M. and Okakurat, T. 1995. Oil Production from Algal Cells of Dunaliella tertiolecta by Direct Thermochemical Liquefaction. Fuel, 74: 1735–1738.
9. Oh, H-M., Lee, S. J., Park, M-H., Kim, H-S., Kim, H-C., Yoon, J-H., Kwon, G-S. and Yoon, B-D. 2001. Harvesting of Chlorella Vulgaris Using a Bioflocculant from Paenibacillus sp. AM49. Biotechnol. Letters, 23: 1229-1234.
10. Papazi, A., Makridis, P. and Divanach,P. 2010. Harvesting Clorella minutissima Using Cell Coagulants. J. Appl. Phycol., 22: 349-355.
11. Phalakornkule, C., Polgumhang, S., and Tongdaung, W. 2009. Performance of Electrocoagulation Process in Treating Directy Dye: Batch and Continuous up Flow Process. World Academy Sci. Technol., 57: 277-282.
12. Price, C. A., Mendiola-Morgenthaler, L. R., Goldstein, M., Breden, E. N. and Guillard, R. R. L. 1974. Harvest of Planktonic Marine Algae by Centrifugation into Gradients of Silica in the CF-6 Continuous Flow Zonal Rotor. Biol. Bull., 147: 136–145.
Journal of Agricultural Science and Technology
Volume 15, Issue 5
September and October 2013
Pages 879-887