Fig. 2From: Sequential phototrophic–mixotrophic cultivation of oleaginous microalga Graesiella sp. WBG-1 in a 1000 m2 open raceway pondChanges of nitrate (orange circle) and acetate (blue up triangle) concentrations under different acetate feeding strategies. The Graesiella cultures were supplied with the same amount of nitrate (~ 1.3 mM) at the beginning, and acetate sodium were supplemented either by fed-batch mode during the whole culture period (E-FB strategy, a), before nitrate depletion (A-FB strategy, b) and after nitrate depletion (P-FB strategy, c), or by batch mode before nitrate depletion (A-B strategy, e) and after nitrate depletion (P-B strategy, f). The phototrophic culture (d) was not supplemented with any organic carbon during cultivationBack to article page