Synechocystis salina: potential bioactivity and combined extraction of added-value metabolites

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 O 2 •− , 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.