Taxonomic study of exopolysaccharide-producing, moderately halophilic bacteria isolated from hypersaline environments in Morocco

A total of 46 strains of moderately halophilic bacteria were isolated from various solar salterns in Morocco, All the strains had the ability to produce exopolysaccharides. We studied their phenotypes by morphological and physiological observations, biochemical and nutritional testing and antimicrobial susceptibility The results were subjected to numerical analysis using the Simple Matching (S(SM)) coefficient and clustered by the unweighted-pair-group method of association (UPGMA). Two phena were obtained at an 80% similarity level. Representative strains from both phena were chosen to determine their DNA base composition and the percentage of DNA-DNA similarity compared to reference strains. Bacteria belonging to phenon A could be included within the genus Halomonas, although they were not closely related to any of its hitherto recognised species. Strains of phenon B were phenotypically related to the moderately halophilic species of Bacillus, bur DNA relatedness studies showed that they were not intimately related to them neither to the species of the genus Halobacillus. These results suggest that the exopolysaccharide-producing strains may well constitute new taxa of moderately halophilic bacteria.