A Taxonomic Study of Heterotrophic Halophilic and Non- halophilic Bacteria from a Solar Saltern

Abstract

A total of 564 strains of heterotrophic non-halophilic, marine, moderately halophilic and extremely halophilic bacteria was isolated from a saltern located near Huelva, SW Spain, facing the Atlantic Ocean. With the exception of the extremely halophilic bacteria, these were analysed by numerical techniques using the simple matching (SsM) coefficient and clustering was achieved using the unweighted pair group method with averages (UPGMA) algorithm. At the 72-504 similarity level, a different number of phenons was found for each salinity group of bacteria. Of the 154 non-halophilic strains, the majority were recovered in 10 phenons, representing members of the genera Staphylococcus, Bacillus and Micrococcus. The 1 38 marine strains, with the exception of 24 strains, clustered into 12 phenons; seven phenons were assigned to the suprageneric grouping Pseudomonas-Alteromonas-Deleya, and the other phenons to Micrococcus, Staphylococcus, Bacillus and Vibrio. The 140 moderately halophilic strains grouped into eight phenons, with only 1 1 strains left unassigned. The majority of these isolates were assigned to the genus Deleya (two phenons) and they showed great similarity with the recently described species D. halophila, isolated from hypersaline soils. Four phenons comprised microorganisms with phenotypic characteristics very similar to the moderately halophilic Vibrio costicola. Two phenons were assigned to the genera Flavobacterium and Acinetobacter but these strains were not similar to previously described species. Of the 145 extremely halophilic isolates studied, the most important group was identified as belonging to the species Halobacterium salinarium (86 strains), followed by H. saccharovorum (20 strains), H. vallismortis (19 strains), Haloarcula hispanica ( I 2 strains) and Halobacterium mediterranei (7 strains). Only one coccus was isolated, with characteristics very similar to those of Halococcus morrhuae.