Food Microbiology

Background: Marine salterns are excellent sites for studying the dynamics of the prokaryotic biodiversity at increasing salt concentrations. Metagenomics offers the most direct approach for reliably assessing the microbial diversity including uncultivable prokaryotes. Salterns of Margherita di Savoia (MdS) are located on the East-cost of South Italy. They are the largest salterns in Europe, with a yet unexplored microbiota composition.

 

Objective: Defining the microbiota composition of the salterns of MdS in ponds with increasing salt concentrations. Methodology: eDNA purified from nine ponds with salt concentration in the 4.9-36% range was used for PCR amplification of the V5-V6 hypervariable region of the 16S rRNA gene. NGS of amplicon libraries was carried out by the Illumina MiSeq platform. Obtained reads were analyzed using the BioMas software for taxonomic classification.

 

Results & Conclusions: The microbiota composition of the MdS salterns resulted in a peculiar composition of prokaryotes, quantitatively different from that of other salterns of the Mediterranean area. For example, Archaea are absent at low salt concentrations (4.9-8.4%) and reach their highest concentrations (30-35%) in the high-salinity ponds. In similar ponds of the salterns of Santa Pola (Spain), their presence has been estimated around 90%. Conversely, in the high-salinity ponds of the MdS salterns, the Eubacteria Salinibacter genus is the most represented genus. This study is of particular interest, not only to define the microbiota composition in different salt concentrations, but also for better addressing future functional metagenomics analysis aimed at the identification of biotechnological useful extremozymes.