Probiotic properties of halophilic Bacillus strains enhance protection of Artemia culture against pathogenic Vibrio

We characterized 3 halophilic Bacillus strains isolated from Tunisian hypersaline environments. Sequencing analyses showed that these bacteria corresponded to the genus Bacillus sp. Antagonism assay revealed that these strains have an inhibitory effect against tested pathogenic bacteria. Qualitative analysis of biofilm revealed that Bacillus strains were unable to produce slime. Furthermore, the investigated strains were fairly adhesive to polystyrene with values ranging from 0.10 to 0.32 at 595 nm. Cell surface hydrophobicity values ranged between 10 and 42%. Pathogenicity and toxicity assays demonstrated that the tested strains were not pathogenic or toxic to the host. Challenge tests performed with Artemia larvae provided evidence that the tested Bacillus strains enhance the protection of Artemia culture against pathogens. These strains are probiotic candidates for Artemia culture.