Diversity of extremely halophilic cultivable prokaryotes in Mediterranean, Atlantic and Pacific solar salterns: Evidence that unexplored sites constitute sources of cultivable novelty

Abstract

The culturable fraction of aerobic, heterotrophic and extremely halophilic microbiota retrieved from sediment and brine samples of eight sampling sites in the Mediterranean, Canary Islands and Chile was studied by means of a tandem approach combining large-scale cultivation, MALDI-TOF MS targeting whole cell biomass, and phylogenetic reconstruction based on 16S rRNA gene analysis. The approach allowed the identification of more than 4200 strains and a comparison between different sampling sites. The results indicated that the method constituted an excellent tool for the discovery of taxonomic novelty. Four new genera and nine new species could be identified within the archaeal family Halobacteriaceae, as well as one new bacterial species, and a representative of Salinibacter ruber phylotype II, a group that had been refractory to isolation for the last fifteen years. Altogether, the results indicated that in order to provide better yields for the retrieval of novel taxa from the environment, performance of non-redundant environment sampling is recommended together with the screening of large sets of strains.

Keywords: Halophilic; Large-scale cultivation; MALDI-TOF MS; OPUs; OTUs; Salterns.