Cultivation of the benthic microalga Prorocentrum lima for the production of diarrhetic shellfish poisoning toxins in a vertical flat photobioreactor

•The cultivation conditions for DSP toxin-containing Prorocentrum lima were optimized.•A method for large-volume cultivation of P. lima using photobioreactor was developed.•P. lima exhibits good growth performance and toxin production in the photobioreactor.•A SWDSC method was proposed and used to harvest of the benthic microalgae cells.•The total contents of the DSP toxins accounted for 3.6% of the dry microalgal powder.

In this study, the cultivation conditions of Prorocentrumlima, including temperature, nutrient concentration, photoperiod, and salinity were observed, and then an effective method for the large-volume cultivation of P. lima using a vertical flat photobioreactor was developed for the first time. The maximum cell concentrations and toxin contents of P. lima cultured in the photobioreactor were reached after a 35 days cultivation. Moreover, a step-wise double-sedimentation centrifugation method was used to harvest the microalgae cells, with the harvest rate of 89%. Toxin analysis of dry microalgal powder indicated that OA and DTX1 contents were 15.2 and 21.6 mg g−1, respectively. These results verify that the culture method using the proposed photobioreactor is effective to massively produce DSP toxin-containing P. lima. This study may serve as a guide for the large-scale production of toxin-producing red-tide benthic microalgae.