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Few studies have focused on the biotechnological potential of the marine cyanobacterium Synechocystis salina, in particular its bioactive metabolites. Hence, an opportunity exists to explore various solvent combinations in attempts to improve extraction of cellular contents of metabolites with antioxidant features as a part of a structured attempt to determine whether S. salina LEGE 06,155 holds a promise for industrial exploitation. Extracts were obtained by single extractions with four GRAS solvents: hexane (H), acetone (A), ethanol (E), and buffer phosphate (PBS) (series A) and successive extractions: H-E-PBS (series B), H-A-PBS (series C), and H-A-E-PBS (series D). The yields, antioxidant capacity, and cytotoxicity of the extracts, as well their content in pigments, lipids, and phenolic compounds were assessed. The combination of solvents of series B produced the highest yield of extraction, of 33.56%. Aqueous extracts for single (series A) and successive extractions (series B and C) presented the highest antioxidant capacity, for ABTS•+ and NO•−, respectively, and had a high content of phycobiliproteins (PBPs). The acetonic (series A) and ethanolic (series B) extracts also showed high antioxidant capacity, in particular for DPPH• and O2•−, respectively. Overall, organic extracts did not show signs of cytotoxicity. Series B extraction enhanced general pigment content, yet single extraction with ethanol (series A) produced the highest content in carotenoids, in particular echinenone and β-carotene, and PBS (series A) improved PBPs content. The lipid content was enhanced in series A (ethanol), while the total phenolic content was improved in series B. Synechocystis has accordingly demonstrated potential for eventual exploitation as biotechnological resource, in terms value-added compounds with antioxidant features. [ABSTRACT FROM AUTHOR]

A cyanobacterium of the genus Chroococcidiopsis has been recently unveiled to go to Mars, owing to its unique ability to stand harsh environmental conditions. Nevertheless, it has been little characterized in terms of other biotechnological applications. The aim of this study was thus to explore the biotechnological potential of Chroococcidiopsis sp. LEGE 06174, using GRAS (generally recognized as safe) solvents for the combined extraction of bioactive compounds. Due to its mucilaginous sheath, sulfuric acid, NaOH, PBS, DMSO 20%, DMSO 100%, and acetone were tested as preliminary treatment—in attempts to enhance pigment extraction. Extracts were then obtained by several series of successive extractions: phosphate-buffered saline (PBS) (serie A), ethanol-PBS (serie B), acetone-PBS (serie C), methanol-PBS (serie D), and acetone-methanol-PBS (serie E). Such extracts were screened for antioxidant capacity, cytotoxicity, and physicochemical characterization in terms of polysaccharides, pigments, and total phenolic compounds. Pre-treatment with PBS proved the most effective toward overall pigment extraction and dissolution of the said mucilaginous sheath. Chroococcidiopsis sp. extracts have unfolded some interesting bioactive features, particularly upon pre-treatment with PBS—i.e., high antioxidant capacity and high content in polysaccharides, scytonemin, phycobiliproteins, and phenolic compounds. The highest total pigment content was obtained in serie D, particularly carotenoids, whereas the highest level of phenolic compounds was found in serie B. All in all, Chroococcidiopsis sp. appears to constitute a significant biotechnological resource worthy of further exploitation in terms of high added-value compounds. [ABSTRACT FROM AUTHOR]

Integrated multitrophic aquaculture (IMTA) has the potential to mitigate environmental impacts from fed aquaculture, by providing nutrient bioremediation while producing economically valuable seaweed biomass with biotechnological interest. Ulva sp. and Gracilaria sp. are species with recognised nutrient bioremediation potential, being promising candidates for association with recirculating aquaculture systems (RAS). Therefore, the performance of these species was evaluated in terms of growth rates, productivity, nutrient uptake rate and biochemical composition, when cultivated associated with Senegalese Sole (Solea senegalensis) aquaculture operating in RAS. Although both species showed the capacity to grow and uptake nutrients in this water, Ulva sp. presented higher growth (5.6 ± 1.1% day−1), and nutrient uptake (C = 93.7 ± 20.3 g m−2 week−1, N = 13.0 ± 2.86 g m−2 week−1) performance. Ulva sp. showed a higher content in chlorophyll a (2.51 ± 0.25 mg g−1 DW) and carotenoids (0.58 ± 0.08 mg g−1 DW), and a higher antioxidant capacity (ethanolic extracts), whereas Gracilaria sp. presented a higher protein content (25.8 ± 1.3% DW), and may be considered a rich source of phycobiliproteins (17.40 ± 2.08 mg g−1 DW). Thus, both species are valuable from a biotechnological perspective, having high potential for application in different industries. [ABSTRACT FROM AUTHOR]