Notes on the Cultivation of Two Mixotrophic Species and Their Ciliate Prey .

Kleptoplastic mixotrophic species of the genus are cultured by feeding with the ciliate , itself a kleptoplastic mixotroph, that in turn feeds on cryptophytes of the // (TPG) clade. Optimal culture media for phototrophic growth of and from the Galician Rías (northwest Spain) and culture media and cryptophyte prey for from Huelva (southwest Spain) used to feed , were investigated. Phototrophic growth rates and yields were maximal when and were grown in ammonia-containing K(-Si) medium versus f/2(-Si) or L1(-Si) media. cultures were scaled up to 18 L in a photobioreactor. Large differences in cell toxin quota were observed in the same strains under different experimental conditions. Yields and duration of exponential growth were maximal for from Huelva when fed from the same region, versus from the Galician Rías or and . Limitations for mass cultivation of northern strains with southern were overcome using more favorable (1:20) : ratios. These subtleties highlight the ciliate strain-specific response to prey and its importance to mass production of and cultures.