The aquaculture industry requires green solutions to solve several environmental challenges, including adequate wastewater remediation and natural drug applications to treat bacteria- and virus-related diseases. This study investigated the feasibility of cultivating the dinoflagellate Durusdinium glynnii in aquaculture wastewater from shrimp rearing in a synbiotic system (AWW-SS), with different dilutions of f/2 medium (FM). Interestingly, D. glynnii demonstrated enhanced growth in all AWW–SS treatments compared to the control (FM). The highest growth rates were achieved at AWW-SS:FM dilutions of 75:25 and 50:50. The removal of total nitrogen and total phosphorus reached 50.1 and 71.7%, respectively, of the crude AWW–SS. Biomass extracts of D. glynnii grown with AWW–SS were able to inhibit the growth of the bacteria Vibrio parahaemolyticus (inhibition zone of 10.0 ± 1.7 mm) and V. vulnificus (inhibition zone of 11.7 ± 1.5 mm). The presented results demonstrate that the dinoflagellate D. glynnii is a potential candidate for the development of circularity for sustainable aquaculture production, particularly by producing anti–Vibrio compounds at a near-zero cost.

This study investigated the effects of salinity on the growth and cell morphotype of the coral-associated dinoflagellate Durusdinium glynnii under two acclimation strategies: abrupt saline shock (S5) and gradual reduction (S2). Results revealed optimal growth rates (µ = 0.22–0.35 day⁻¹) at salinities of 20–30 g L⁻¹, while extreme conditions (10 and 40 g L⁻¹) significantly inhibited development. The S2 strategy enabled adaptation to salinities as low as 16 g L⁻¹, maintaining higher cell densities compared to the S5 method. Gradual salinity reduction also influenced cellular morphology: below 12 g L⁻¹, a predominant shift occurred from motile forms (mastigotes) to non-motile spherical structures (coccoid), suggesting an adaptive response to osmotic stress, gradually reducing the growth rate due to the lower reproductive rate of coccoid cells, as previously reported in studies. The findings conclude that D. glynnii is a euryhaline species, tolerant of moderate salinity variations (16–30 g L⁻¹) but limited under extreme conditions. Its morphological plasticity and gradual acclimation capacity highlight its potential for cultivation in brackish environments and biomass production for biotechnological applications, such as antioxidants and antimicrobials. The data provide a foundation for future studies on molecular mechanisms of salinity tolerance, essential for coral conservation strategies and bioprospecting efforts.

Microalgae are photosynthetic organisms with rapid growth and high biochemical diversity, capable of thriving in a variety of environments. Among them, dinoflagellates, particularly symbiotic species like Durusdinium glynnii, have gained attention due to their potential for biotechnological applications, especially in the production of valuable fatty acids. However, the delicate cultivation of dinoflagellates remains a challenge due to their sensitivity to shear stress and complex morphology. In this study, we evaluated the influence of inoculum percentage (10%, 25%, and 50%) on the growth performance and fatty acid profile of D. glynnii during a scale-up process from test tubes to a pilot-scale photobioreactor. Higher inoculum concentrations (50%) promoted faster acclimatization, higher specific growth rates (µ_max), and greater final biomass densities, optimizing the cultivation process. Meanwhile, lower inoculum concentrations (10%) favored the accumulation of polyunsaturated fatty acids, particularly DHA (C22:6n3), indicating a trade-off between biomass productivity and fatty acid biosynthesis. Overall, D. glynnii demonstrated robust adaptability, reinforcing its potential as a sustainable source of bioactive compounds. Further studies focusing on cellular and metabolic pathways are needed to better elucidate the mechanisms underlying lipid production and growth in this promising species.

The growing need for sustainable protein sources in aquaculture has led to interest in microalgae, such as Chlorella vulgaris, known for its high nutritional value. One promising strategy for delivering these nutrients is through bioencapsulation in Daphnia magna, a common live feed used in aquaculture. This study evaluated the effect of including D. magna bioencapsulated with C. vulgaris as live feed for marine shrimp Penaeus vannamei post-larvae. Shrimp were fed at two D. magna densities (5 and 10 per shrimp, 5DF and 10DF), offered weekly, and compared with a control group receiving only commercial feed (F) for 36 days in a synbiotic nursery system. Water quality, zootechnical performance, protein, and lipid content of the shrimp were analyzed using correlation analyses, nonlinear prediction models, and principal component analysis (PCA). Shrimp fed with the 10DF treatment exhibited superior zootechnical performance, characterized by a lower feed conversion ratio (1.01) and higher feed efficiency (99.97%), protein (70.91%), and lipid (32.45%) content in comparison with the 5DF and control. Quadratic regression predictive models indicated the possibility of further testing higher concentrations of D. magna per shrimp. The results indicates that the use of C. vulgaris bioencapsulated in D. magna as live feed for P. vannamei is a promising approach to improve shrimp diets and increase production in aquaculture.