Optimum medium for large-scale culture of Tetraselmis tetrathele

The prasinophyte Tetraselmis tetrathele is an alga commonly used as livefood for aquatic animal larvae. The alga is usually cultured in Guillard& Ryther medium (Guillard F) or a fertilizer enriched seawater mediumfor the large-scale culture of Nannochloropsis. However, Guillard F is toocomplicated to use for large-scale culture, and some fertilizers are impureand insoluble. A new enriched seawater medium for the large-scale culture ofT. tetrathele (ES-T.T.) was formulated by modifying the Guillard F medium.NaNO3, NaH2PO4, Fe-EDTA andMnCl2were selected as essential additives for the medium bysystematically removing each additive of Guillard F. Results from axenicculture experiments, using an artificial seawater medium, the requiredamount of these additives was estimated to be, 150 mg NaNO3,10 mg NaH2PO4 · 2H20, 15 mgFe-EDTA and 360 µg MnCl2 · 4H2O,per liter of seawater. The productive rate of T. tetrathele in ES-T.T. washigher than in a fertilized medium in a 100 liter outdoor cultureexperiment. In 10 liter indoor culture experiments, no significantdifference was detected in production rates between ES-T.T. and Guillard F.Therefore, ES-T.T. is simple and effective to use as a large-scale culturemedium for T. tetrathele.