초록
Continuous culture of fresh water microalgae Scenedesmus obliquus was developed in a two-stage photobioreactor, avoiding the intermediate harvesting step to achieve a half-way point between the progressive and the sudden N-starvation strategies, guaranteeing light limited conditions in the first stage and N-stress conditions in the second stage. This methodology resulted in biomass productivity values at the best dilution rate (0.118days<SUP>-1</SUP>) of 15.25+/-1.06gm<SUP>-2</SUP>d<SUP>-1</SUP>, slightly higher than that expected according to batch experiment (12.90+/-0.75gm<SUP>-2</SUP>d<SUP>-1</SUP>). The dilution rate that maximized the lipid content was coincident with that for the maximum biomass productivity, resulting in a intensification of the lipid productivity. Microalgae can be successfully cultured in reused medium clarified by high pH flocculation-sedimentation and neutralized by bubbling the photobioreactors outlet CO<SUB>2</SUB> current through it. Microalgae flocculation with NaOH does not result in a variation of the obtained lipid profile.