The rapid expansion of shrimp aquaculture has led to the generation of nutrient-rich effluents, which contribute to environmental degradation if inadequately managed. This study evaluated the potential of Dunaliella salina for the reuse of shrimp aquaculture wastewater (SAW) in biofloc production systems under varying dilution levels (0%, 25%, and 50%) and the simultaneous production of high-value biomass. Growth kinetics were modeled using a four-parameter logistic model, and nutrient removal, biochemical composition, and fatty acid profile were assessed. D. salina exhibited substantial growth in undiluted SAW, achieving over 80% removal of total nitrogen and reducing the organic load, as measured by a chemical oxygen demand reduction of more than 79%. In SAW treatments, the protein content ranged from 24.7% to 26.3%, while the lipid content reached up to 67.1% in a 25% SAW dilution. Chlorophyll a and total carotenoids were measured at 5.3–7 µg/mL and 4.1–5.7 µg/mL, respectively, in SAW treatments. The polyunsaturated fatty acid content in undiluted SAW was 34.5%, with α-linolenic acid (C18:3n3) and linoleic acid (C18:2n6) comprising 12% and 7.5%, respectively. This study demonstrates the ability of D. salina to valorize shrimp aquaculture wastewater in biofloc systems into lipid-rich, bioactive biomass, supporting its use in integrated aquaculture biotechnology systems for sustainable wastewater management and bioproduct generation.

<!--Galleys --> <!--Full Text:--> PDF <!--END GALLEYS---> Abstract Microalgae can accumulate lipids during the stationary growth phase, but little information is available about fatty acid profile changes during this phase to determine the best harvesting time in respect to lipid content. In this study, Dunaliella sp. was cultured in F/2 medium at three different photon flux densities (380, 226 and 8.2 μmol photon m^-2 s^-1) and three different glycerol concentrations (0, 10 and 20 g L^-1). Samples were taken during the stationary phase to assess lipid content and fatty acid profile variations. Microalgal biomass production was higher at 380 and 226 μmol photon m^-2 s^-1 than at 8.2 μmol photon m^-2 s^-1 in accord to light limitation. The maximum lipid content (345.78 mg g^-1) was achieved at 8.2 μmol photon m^-2 s^-1 and 20 g L^-1 glycerol at day 12, similar to that achieved at day 9 (334.16 mg g^-1). The maximum polyunsaturated fatty acid amount (65.30 μg mg^-1) was achieved at day 7 of culture without glycerol addition, decreasing in proportion over time. So, the best conditions and harvesting time in respect to fatty acid quality would be at 380 μmol photon m^-2 s^-1 without glycerol addition and after 7 days of culture.

La investigación se enfocó en la determinación del contenido proteico y nutracéutico en el ciliado de vida libre Paramecium aurelia, que fue aislado de una fuente silvestre y se identi có. Los cultivos axénicos de P. aurelia se realizaron en un bio-reactor automatizado con control de pH a 7.0, 28 ◦C, oxígeno disuelto superior a 2 mg L^-1 y agitación a 70 rpm por 72 h. El medio de cultivo se integró con 700 mL de infusión de lechuga y trigo, diluidos en 1 L de agua destilada e inóculo de 300 mL con 3 x 103 células mL^-1. De estos cultivos se obtuvieron 74.1 mg L^-1 de biomasa seca, 48.6 % de proteínas y 37.6 % de lípidos, conformados principalmente por ácidos grasos: oleico (20.8 %), linoleico (11.1 %), gama-linolénico (3.6 %) y araquidónico (6.0 %). Las vitaminas presentes fueron: A (retinol, 81.27 μg g^-1), E (tocoferol, 28.73 mg g^-1) y D3 (colecalciferol, 4.49 mg g^-1). La biomasa de P. aurelia, podría constituir una fuente importante de proteína y de sustancias nutracéuticas.