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New culture approaches for yessotoxin production from the dinoflagellate Protoceratium reticulatum

Abstract:

Fed-batch and perfusion cultures were carried out in a traditional glass 2-L bioreactor with the toxic dinoflagellate Protoceratium reticulatum. The maximum cell concentration obtained was 2.3 × 105 cell·mL-1, which is almost 1 order of magnitude higher than the maximum previously referenced for this species. L1 medium was shown to be clearly deficient in nitrate and phosphate for this strain, and addition of highly concentrated aliquots of these nutrients allowed higher cell concentrations to be obtained. This species consumed high amounts of nitrate and phosphate, 2.1 × 10-3 and 2.3 × 10-4 μmol·h-1·cell-1, respectively. However, this consumption produced a very low number of cells compared to other classes of microalgae, indicating that this species is, like other dinoflagellates, a poor competitor in terms of utilization of inorganic nutrients. Higher production of toxins and pigments was strongly associated with cell number in the culture, with maximum values of 700 ng·mL-1 and 1321 μg·mL-1, respectively. Most yessotoxins remained within the cells and not in the cell-free culture medium, and their production was not related to either the age of the culture or the cell growth phase. © 2007 American Chemical Society and American Institute of Chemical Engineers.