Journal of Applied Phycology

, Volume 24, Issue 6, pp 1667–1679 | Cite as

A comparative study of the coagulation behaviour of marine microalgae

  • R. J. Eldridge
  • D. R. A. Hill
  • B. R. Gladman


Coagulation is an important step in the harvesting of algal biomass. This paper presents experimental results for a variety of prospective marine microalgal species using several inorganic and organic coagulants. Tetraselmis suecica and Chlorococcum sp. are readily coagulated using alum or iron(III) sulphate without any pH adjustment; doses of 3–5 mg L−1 or 0.2 mmol m−2 of Al3+ or Fe3+ yielding cell recoveries above 90 % after only 5-min settling. Nannochloropsis salina, Dunaliella tertiolecta and Isochrysis galbana are harder to coagulate and require at least two times more coagulant to achieve similar recoveries. Several cationic polyacrylamides were investigated but were less effective than Al3+ or Fe3+. Addition of NaOH to control pH improved the coagulation efficiency of N. salina but not of D. tertiolecta. The high coagulant demand of N. salina is due in part to its small size and large surface area, while that of D. tertiolecta may be attributable to its high production of extracellular polymer. The implications of cell surface properties for coagulation efficiency are discussed. At the coagulant doses used herein, settled cells remain viable. Resuspension is a potential problem with some species, arising either from cell motility or from flotation of flocs by oxygen bubbles generated by photosynthesis. These effects can be eliminated by small additions of chlorine or by settling the algae in the dark.


Microalgae Dewatering Harvesting Coagulation Flocculation Biofuels 



This work was funded by an ARC linkage grant with financial support from Biofuels Pty Ltd. We thank Tina Hines and Kerrie Browne at Water Studies Centre for DOC and Fe analyses. Al analyses were performed by ALS Laboratory Group, Springvale, Victoria, Australia. The authors also thank Sherrie Caarels for her monitoring work and maintenance of the algal cultures.


  1. Bernhardt H, Clasen J (1991) Flocculation of micro-organisms. J Water Supply Res Technol 40(2):76–87Google Scholar
  2. Bhaskar PV, Bhosle NB (2005) Microbial extracellular polymeric substances in marine biogeochemical processes. Curr Sci India 88:45–53Google Scholar
  3. Bilanovic D, Shelef G, Sukenik A (1988) Flocculation of microalgae with cationic polymers—effects of medium salinity. Biomass 17:65–76CrossRefGoogle Scholar
  4. Bolto B, Gregory J (2007) Organic polyelectrolytes in water treatment. Water Res 41:2301–2324PubMedCrossRefGoogle Scholar
  5. Borowitzka MA, Siva CJ (2007) The taxonomy of the genus Dunaliella (Chlorophyta) with emphasis on the marine and halophilic species. J Appl Phycol 19:567–590CrossRefGoogle Scholar
  6. Boussiba S, Sandbank E, Shelef G, Cohen Z, Vonshak A, Ben-Amotz A, Arad S, Richmond A (1988) Outdoor cultivation of the marine microalga Isochrysis galbana in open reactors. Aquaculture 72:247–253CrossRefGoogle Scholar
  7. Duan J, Gregory J (2003) Coagulation by hydrolysing metal salts. Adv Colloid Interf Sci 100:475–502CrossRefGoogle Scholar
  8. Gelin F, Boogers L, Noordeloos AAM, Sinninghe Damsté JS, Riegman R, De Leeuw JW (1996) Resistant biomacromolecules in marine microalgae of the classes Eustigmatophyceae and Chlorophyceae: geochemical implications. Org Ceochem 26:659–675Google Scholar
  9. Gelin F, Volkman JK, Largeau C, Derenne S, Sinninghe Damsté JS, De Leeuw JW (1999) Distribution of aliphatic, nonhydrolyzable biopolymers in marine microalgae. Org Geochem 30:147–159CrossRefGoogle Scholar
  10. Green JC, Pienaar RN (1977) The taxonomy of the order Isochrysidales (Prymnesiophyceae) with special reference to the genera Isochrysis Parke, Dicrateria Parke and Imantonia Reynolds. J Mar Biol Assoc UK 57:7–17CrossRefGoogle Scholar
  11. Guillard RRL, Ryther JH (1962) Studies of marine planktonic diatoms. I. Cyclotella nana Hustedt and Detonula confervacea (Cleve). Gran. Can J Microbiol 8:229–239PubMedCrossRefGoogle Scholar
  12. Guillard RRL, Wangersky PJ (1958) The production of extracellular carbohydrates by some marine flagellates. Limnol Oceanogr 3:449–454CrossRefGoogle Scholar
  13. Hellebust JA (1965) Excretion of some organic compounds by marine phytoplankton. Limnol Oceanogr 10:192–206CrossRefGoogle Scholar
  14. Henderson RK, Parsons SA, Jefferson B (2008) Surfactant as bubble surface modifiers in the flotation of algae: dissolved air flotation that utilizes a chemically modified bubble surface. Environ Sci Technol 42:4883–4888PubMedCrossRefGoogle Scholar
  15. Hibberd DJ, Leedale GF (1971) A new algal class—the Eustigmatophyceae. Taxon 20:523–525CrossRefGoogle Scholar
  16. Hunter RJ (2001) Foundations of colloid science. Oxford University Press, New York, p 616Google Scholar
  17. Huntsman SA (1972) Organic excretion by Dunaliella tertiolecta. J Phycol 8:59–63Google Scholar
  18. Ives K (1959) The significance of surface electric charge on algae in water purification. J Biochem Microbiol Technol Eng 1:37–47CrossRefGoogle Scholar
  19. Kiørboe T, Hansen JLS (1993) Phytoplankton aggregate formation: observations of patterns and mechanisms of cell sticking and the significance of exopolymeric material. J Plankton Res 15:993–1018CrossRefGoogle Scholar
  20. Knuckey R, Brown M, Robert R, Frampton D (2006) Production of microalgal concentrates by flocculation and their assessment as aquaculture feeds. Aquacult Eng 35:300–313CrossRefGoogle Scholar
  21. Kormas KA (2005) Bacterioplankton growth on extracellular organic carbon from marine microalgal cultures. Biol Mar 46:241–251Google Scholar
  22. Levy N, Magdassi S, Bar-Or Y (1992) Physico-chemical aspects in flocculation of bentonite suspensions by a cyanobacterial bioflocculant. Water Res 26:249–254CrossRefGoogle Scholar
  23. Lubián LM (1989) Concentrating cultured marine microalgae with chitosan. Aquacult Eng 8:257–265CrossRefGoogle Scholar
  24. Ma J, Liu W (2002) Effectiveness and mechanism of potassium ferrate(VI) preoxidation for algae removal by coagulation. Water Res 36:871–878PubMedCrossRefGoogle Scholar
  25. Marker AFH (1965) Extracellular carbohycrates liberation in the flagellates Isochrysis galbana and Prymnesium parvum. J Mar Biol Assoc UK 45:755–772CrossRefGoogle Scholar
  26. McGarry M (1970) Algal flocculation with aluminum sulfate and polyelectrolytes. Res J Water Pollut C 42:191–201Google Scholar
  27. Miller DH (2006) Cell wall chemistry and ultrastructure of Chlorococcum oleofaciens (Chlorophyceae). J Phycol 14:189–194CrossRefGoogle Scholar
  28. Morales J, de la Noüe J, Picard G (1985) Harvesting marine microalgae species by chitosan flocculation. Aquacult Eng 4:257–270CrossRefGoogle Scholar
  29. Oliveira L, Bisalputra T, Antia NJ (1980) Ultrastructural observation of the surface coat of Dunaliella tertiolecta from staining with cationic dyes and enzyme treatments. New Phytol 85:385–392CrossRefGoogle Scholar
  30. Palmer DA, Bell JLS (1994) Aluminum speciation and equilibria in aqueous solution: IV. A potentiometric study of aluminum acetate complexation in acidic NaCl brines to 150°C. Geochim Cosmochim Acta 58:65 l–659CrossRefGoogle Scholar
  31. Parke M (1949) Studies on marine flagellates. J Mar Biol Assoc UK 28:255–288CrossRefGoogle Scholar
  32. Passow U, Alldredge AL, Logan BE (1994) The role of particulate carbohydrate exudates in the flocculation of diatom blooms. Deep-Sea Res 41:335–357CrossRefGoogle Scholar
  33. Pieterse AJH, Cloot A (1997) Algal cells and coagulation, flocculation and sedimentation processes. Water Sci Technol 36:111–118Google Scholar
  34. Plummer JD, Edzwald JK (2001) Effect of ozone on algae as precursors for trihalomethane and haloacetic acid production. Environ Sci Technol 35:3661–3668PubMedCrossRefGoogle Scholar
  35. Plummer JD, Edzwald JK (2002) Effects of chlorine and ozone on algal cell properties and removal of algae by coagulation. J Water Supply Res Technol 51:307–318Google Scholar
  36. Pushparaj B, Pelosi E, Torzillo G, Materassi R (1993) Microbial biomass recovery using a synthetic cationic polymer. Bioresour Technol 43:59–62CrossRefGoogle Scholar
  37. Romanovicz DK (1981) Scale formation in flagellates. In: Kiermayer O (ed) Cytomorphogenesis in plants. Springer, Berlin, pp 27–62CrossRefGoogle Scholar
  38. Salehizadeh H, Shojaosadati SA (2001) Extracellular biopolymeric flocculants—recent trends and biotechnological importance. Biotechnol Adv 19:371–385PubMedCrossRefGoogle Scholar
  39. Schenk PM, Thomas-Hall SR, Stephens E, Marx UC, Mussgnug JH, Posten C, Kruse O, Hankamer B (2008) Second generation biofuels: high-efficiency microalgae for biodiesel production. Bioenerg Res 1:20–43CrossRefGoogle Scholar
  40. Sukenik A, Teltch B, Wachs AW, Shelef G, Nir I, Levanon D (1987) Effect of oxidants on microalgal flocculation. Water Res 21:533–539CrossRefGoogle Scholar
  41. Sukenik A, Bilanovic D, Shelef G (1988) Flocculation of microalgae in brackish and sea waters. Biomass 15:187–199CrossRefGoogle Scholar
  42. Tenney M, Echelberger W, Schuessler R, Pavoni J (1969) Algal flocculation with synthetic organic polyelectrolytes. Appl Environ Microbiol 18:965–971Google Scholar
  43. Wijffels RH, Barbosa MJ (2010) An outlook on microalgal biofuels. Science 329:796Google Scholar
  44. Williams PJB, Laurens LML (2010) Microalgae as biodiesel & biomass feedstocks: review & analysis of the biochemistry, energetics & economics. Energy Environ Sci 3:554–590CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • R. J. Eldridge
    • 1
  • D. R. A. Hill
    • 1
    • 2
  • B. R. Gladman
    • 1
    • 2
  1. 1.Department of Chemical EngineeringMonash UniversityClaytonAustralia
  2. 2.Department of Chemical and Biomolecular EngineeringThe University of MelbourneMelbourneAustralia

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