Sponge-associated cyanobacterial diversity and activity: evidences from the northern Ionian Sea

Sponges (phylum Porifera) host an exceptional microbial diversity. Among microorganisms, which may represent up to 40% of the sponge volume, cyanobacteria are often the most common and important components. The sponge-cyanobacteria association is considered as a mutualistic interaction, in which sponge can provide a protected habitat for cyanobacteria, and cyanobacteria can furnish up to 80% of the host’s energy requirements through photosynthesis. Cyanobacteria also assist in the removal of nitrogenous wastes from the sponge host and can provide biochemical defense by the production of bioactive metabolites (Pagliara et al. 2020). In fact, it is well known that marine cyanobacteria are sources of over 400 bioactive compounds, which may have useful properties, such as antibacterial, antiviral, anticoagulant or anticancer activities (Konstantinou et al. 2021). This study aims to overview the knowledge of the culturable cyanobacteria isolated from the Mediterranean sponge Petrosia ficiformis (Poiret, 1789) in relation to: a) their diversity; b) their biological activities on murine and human cancer lines; c) the chemical characterization of their extracts.