Development of an automatic system for cultivating the bioluminescent heterotrophic dinoflagellate <italic>Noctiluca scintillans</italic> on a 100-liter scale

Abstract

Noctiluca scintillans is a heterotrophic dinoflagellate that causes red-colored oceans during the day (red tides) and glowing oceans at night (bioluminescence). This species feeds on diverse prey, including phytoplankton, heterotrophic protists, and eggs of metazoans. Thus, many scientists have conducted studies on the ecophysiology of this species. It is easy to cultivate N. scintillans at a scale of &lt;1 L, but it is difficult to cultivate them at a scale of &gt;100 L because N. scintillans cells usually stay near the surface, while prey cells stay below the surface in large water tanks. To obtain mass-cultured N. scintillans cells, we developed an automatic system for cultivating N. scintillans on a scale of 100 L. The system consisted of four tanks containing fresh nutrients, the chlorophyte Dunaliella salina as prey, N. scintillans for growth, and N. scintillans for storage, respectively. The light intensities supporting the high growth rates of D. salina and N. scintillans were 300 and 20 μmol photons m-2 s-1, respectively. Twenty liters of D. salina culture from the prey culture tank were transferred to the predator culture tank, and subsequently 20 L of nutrients from the nutrient tank were transferred to the prey culture tank every 2 d. When the volume of N. scintillans in the predator culture tank reached 90 L 6 d later, 70 L of the culture were transferred to the predator storage tank. To prevent N. scintillans cells from being separated from D. salina cells in the predator culture tank, the culture was mixed using an air pump, a sparger, and a stirrer. The highest abundance of N. scintillans in the predator culture tank was 45 cells mL-1, which was more than twice the highest abundance when this dinoflagellate was cultivated manually. This automatic system supplies 100 L of N. scintillans pure culture with a high density every 10 d for diverse experiments on N. scintillans.

Estimation of bioluminescence intensity of the dinoflagellates Noctiluca scintillans, Polykrikos kofoidii, and Alexandrium mediterraneum populations in Korean waters using cell abundance and water temperature

“…The maximum abundance of N. scintillans in Korean waters used in the estimation of its BL popul was as high as 3.5 × 10 6 cells L -1 . The highest abundance of N. scintillans cultivated in our laboratory was 4.5 × 10 4 cells L -1 (You et al 2022). N. scintillans cells tend to float and aggregate at the surface (Tiselius andKiørboe 1998, Padmakumar et al 2010).…”

Short-Term Interactions of Noctiluca scintillans with the Toxic Dinoflagellates Dinophysis acuminata and Alexandrium minutum: Growth, Toxins and Allelopathic Effects

“…In the laboratory, N. scintillans cultures (its red form) have been maintained long term using the chlorophyte Dunaliella salina as prey [ 30 ]. Additionally, Fukuda et al [ 4 ] employed another chlorophyte ( D. tertiolecta ) to detail the life cycle of N. scintillans .…”

“…Additionally, Fukuda et al [ 4 ] employed another chlorophyte ( D. tertiolecta ) to detail the life cycle of N. scintillans . The evolution of N. scintillans cultures with different microalgal prey has been examined in a number of studies [ 12 , 30 , 31 , 32 ], including toxin-producing dinoflagellates [ 32 , 33 , 34 ]. However, the fate of marine biotoxins in plankton communities during the buildup of proliferations by N. scintillans , and the interactions between toxic prey and this organism, remains fairly under-investigated.…”

Effects of aeration and centrifugation conditions on omega-3 fatty acid production by the mixotrophic dinoflagellate Gymnodinium smaydae in a semi-continuous cultivation system on a pilot scale

“…A 10-L semi-continuous cultivation system for G. smaydae was previously developed, and the cell density and fatty acid contents of the species were stably maintained for 43 days (Lim et al 2020). We have successfully developed a 100-L cultivation system for the heterotrophic dinoflagellate Noctiluca scintillans (You et al 2022). However, considering that for some microalgae cultivation conditions on a small scale may differ from those on a larger scale with regard to commercial production (Borowitzka andVonshak 2017, You et al 2022), and the optimized conditions for high production and efficient harvest of G. smaydae in an upscaled system are yet to be identified.…”