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.