Molecular and physiological assessment of Thermospirulina andreolii

The Euganean Thermal District has been known since ancient times for the therapeutic and anti-inflammatory proprieties of its muds, obtained through a traditional maturation process. During the maturation period, a green microbial biofilm, characterized by the presence of filamentous and coccoid cyanobacteria which enrich the muds by synthetizing anti-inflammatory and antioxidant molecules, in particular exopolysaccharides (EPS), lipids and phycobiliproteins. During the characterization of the microbial community of the biofilm deriving from various mud maturation tanks, it has been found that Phormidium sp. ETS05 is the most abundant strain in muds maturating in a 37-47°C and for such reasons it has been studied in previous research. In muds maturation at temperatures higher than 47°C the cyanobacterial community drastically changes, with the disappearance of Phormidium sp. ETS05 and predominance of the newly isolated and characterized Thermospirulina andreolii and Leptolyngbya ETS-13. This work has three main objectives: an initial screening of the best growth conditions in different light intensities and temperatures, a deeper assessment of the EPS and phycobiliproteins productivity of T. andreolii in the best growth condition and finally an initial genome analysis to reconstruct pathways related to lipid and EPS production that can be used for future studies. Growth at 30-40-50°C and light intensities of 10-30-50-100-150-200-300-400 μmol photons m–2 s–1 where tested and it was found that T. andreolii grows better in a range of 100-300 μmol photons m–2 s–1 at a temperature of 40°C. Quantification of chlorophylls and carotenoids, optical density and dry weight were analysed to assess the best growth ranges supplemented by a quantification of the productivity phycobiliproteins and EPSs. The genome of T. andreolii was obtained in collaboration with Prof. Laura Treu and Stefano Campanero, from both Nanopore and Illumina sequences resulting in a genome of 5.429.298 bp, complete at 98% and composed of 7 contigs, this was annotated both with RAST and GhostKOALA and the Fatty acid biosynthesis, initiation (keg module M00082) and elongation (Kegg Module M00083) where reconstructed while genes associated with the EPS synthesis and secretion, knowledge on which is scarce, haven’t been found and require further study.