Molecular and biochemical characterization of cyanobacterial strains isolated from the Ionian Sea (Greece)

The aim of this study was the isolation of new cyanobacterial strains from the Ionian Sea (Greece) and their taxonomic and biochemical characterization. Four cyanobacterial isolates were identified using molecular techniques and were classified to the newly-established genera Baaleninema and Sodaleptolyngbya and the genus Synechocystis. The ability of the isolates to grow under laboratory conditions was evaluated. Baaleninema strains, namely Baaleninema sp. TRL2.1 and Baaleninema simplex ALN4.1, growing in modified artificial seawater produced abundant biomass, exceeding 800 mg L- 1, while Sodaleptolyngbya sp. VNT5.4 and Synechocystis sp. PAT4.6 produced significantly less biomass, yet in notable quantities. In most of the cases the content of the isolates in lipids (i.e., 2.5-9.1 %), which were dominated by saturated and monounsaturated fatty acids and total pigments (i.e., 0.4-1.2 %) can be described as weak. In regard with polysaccharides synthesis both Baaleninema strains produced considerable amounts (i.e., 18.2-23.6 %), while synthesis of these molecules was lower in the other two strains (i.e., 9.4-10.4 %). On the other hand, having Sodaleptolyngbya sp. VNT5.4 as the sole exception, for all strains significant levels of proteins were recorded in the cell mass, approaching or even exceeding 40 % (wt/ wt) in dry biomass. Finally, the isolates were examined for their biofilm-forming capacity, a feature of interest as a cost-effective means of biomass harvesting in large-scale applications and wastewater treatment. Both Baaleninema strains proved to be strong biofilm formers. The biochemical profiles of these new isolates showcased their suitability for use in aquaculture and various industrial applications.