title: Pressurized liquid extraction of toxins from cyanobacterial cells.
abstract: The suitability of pressurized liquid extraction (PLE) of cyanotoxins from cells was investigated. The stability of cyanotoxins (MCYST-RR, MCYST-LR, and anatoxin-a) was evaluated at nine combinations of pressure and temperature (7, 10, and 14 MPa and 60 degrees C, 80 degrees C and 100 degrees C) using 75% (v/v) methanol in water (MeOH) as solvent. Additional experiments investigated the stability of cyanotoxins when water was used as solvent (at a pressure of 14 MPa and a temperature of 40 degrees C, 50 degrees C, 60 degrees C, 80 degrees C, or 100 degrees C). Results using 75% MeOH showed that the MCYST-RR and MCYST-LR were stable under the tested pressures up to 80 degrees C. At 100 degrees C MCYST recovery decreased by 10% to 17%. When water was used as the solvent, no differences in recovery were observed for MCYST-LR, whereas for MCYST-RR, maximum recovery was obtained at 60 degrees C, and degradation occurred at 100 degrees C. In contrast, anatoxin-a was labile under all experimental conditions; the best recoveries (ca. 50%) were obtained at 60 degrees C at the three pressures using 75% MeOH. However, only 17%-23% recovery was obtained with water extraction at all temperatures. The extraction of MCYST-LR and variants from cells (Microcystis aeruginosa, UTCC299) was studied using two solvents, 75% MeOH and 100% water, at 14 MPa and 60 degrees C and 100 degrees C. PLE extracts were compared with extracts obtained with 75% MeOH and ultrasonication. Complete extraction was achieved in both solvents in one 5-min cycle (at 100 degrees C). Although lower recovery was obtained using PLE (79%-105%), shorter extraction time and automation are advantageous over ultrasonication.
authors.affiliation: Chemistry Research Division, Health Canada, Tunney's Pasture, 0800C, Ottawa, Ontario, K1A 0L2, Canada. rocio_aranda-rodriguez@hc-sc.gc.ca
authors.forename: Rocio
authors.initials: R
authors.lastname: Aranda-Rodriguez
authors.forename: Angeline
authors.initials: A
authors.lastname: Tillmanns
authors.forename: Frank M
authors.initials: FM
authors.lastname: Benoit
authors.forename: Frances R
authors.initials: FR
authors.lastname: Pick
authors.forename: Jeromy
authors.initials: J
authors.lastname: Harvie
authors.forename: Lioudmila
authors.initials: L
authors.lastname: Solenaia
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods; D000458:Cyanobacteria / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000032:analysis*; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis*; D011312:Pressure; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D012997:Solvents; C063855:microcystin RR; C057862:cyanoginosin LR