title: Extraction of microalgal toxins by large-scale pumping of seawater in Spain and Norway, and isolation of okadaic acid and dinophysistoxin-2.
abstract: Marine biotoxins from microalgae can accumulate in shellfish and lead to poisoning of human consumers as well as fish, marine mammals and sea birds. Toxicological assessment of the toxins and development of analytical methods require large amounts of high-purity toxins and their metabolites. Although these toxins can be obtained in limited amounts from contaminated shellfish or from microalgal cultures, difficulties arise when the toxin-producing microalga is difficult to culture or its identity is not known. To circumvent this problem, we have developed a large-scale method for solid-phase extraction (SPE) of lipophilic biotoxins from natural microalgal blooms in seawater. To enhance subsequent purification of toxins adsorbed on the column, we included a filtration step to release the toxins from the cells while removing insoluble compounds and cellular debris. The efficacy of the method was illustrated by extraction and purification of okadaic acid and dinophysistoxin-2 from a high-density Dinophysis acuta bloom in Spain and from a mixed bloom containing low densities of D. acuta in Norway. Isolation of the toxins adsorbed on the SPE column was simple and efficient, and results obtained so far indicate that the method is potentially applicable to a wide range of microalgal toxins such as azaspiracids, pectenotoxins, spirolides and microcystins. The method should also be useful for harvesting toxins from large-scale microalgal cultures, and for bioprospecting for and isolation of bioactive natural products from marine and freshwater environments.
authors.affiliation: National Veterinary Institute, PB 8156 Dep., NO-0033 Oslo, Norway. thomas.rundberget@vetinst.no
authors.forename: Thomas
authors.initials: T
authors.lastname: Rundberget
authors.forename: Morten
authors.initials: M
authors.lastname: Sandvik
authors.forename: Kristofer
authors.initials: K
authors.lastname: Larsen
authors.forename: Gemita M
authors.initials: GM
authors.lastname: Pizarro
authors.forename: Beatriz
authors.initials: B
authors.lastname: Reguera
authors.forename: Tonje
authors.initials: T
authors.lastname: Castberg
authors.forename: Eli
authors.initials: E
authors.lastname: Gustad
authors.forename: Jared I
authors.initials: JI
authors.lastname: Loader
authors.forename: Frode
authors.initials: F
authors.lastname: Rise
authors.forename: Alistair L
authors.initials: AL
authors.lastname: Wilkins
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Miles
mesh_terms: D056890:Eukaryota / Q000378:metabolism*; D008387:Marine Toxins / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D009664:Norway; D019319:Okadaic Acid / Q000032:analysis / Q000302:isolation & purification* / Q000031:analogs & derivatives; D011714:Pyrans / Q000032:analysis / Q000302:isolation & purification*; D012623:Seawater / Q000737:chemistry*; D013030:Spain