Etudiant : BAHTI MARYEME

Filière : Master d'excellence: Biotechnologie Alimentaire et Management de la Qualité (BAEMQ)

Encadrant : Pr. BERRADA SANAE

Annèe : 2026

Résumé : Hypersaline environments harbor diverse halotolerant and halophilic microorganisms with promising biotechnological potential. This study investigated cultivable bacteria isolated from the Castro Marim saltern (Algarve, Portugal) through phenotypic characterization, salt-tolerance assays, antimicrobial screening, and 16S rRNA gene sequencing. Ten bacterial isolates were recovered and exhibited different degrees of halotolerance, with several growing at NaCl concentrations up to 20%. Phenotypic screening revealed widespread catalase activity and siderophore production, whereas no detectable hydrolytic enzyme, phosphate-solubilization, or potassium solubilization activities were observed. Antimicrobial activity was evaluated against the pathogenic bacteria Escherichia coli and Staphylococcus aureus, but no inhibition zones were detected under the conditions tested. Molecular identification by 16S rRNA sequencing assigned the selected isolates to the genera Mesobacillus (isolates 1.2 and 3.1), Vreelandella (isolate 5.1), and Maritalea (isolate 6.1), with isolate 6.1 showing the highest similarity to Maritalea mobilis, while the remaining isolates were conservatively identified at the genus level. These findings demonstrate that the Castro Marim saltern harbors a taxonomically diverse community of halotolerant and halophilic bacteria that constitutes a valuable resource for future biotechnological exploration, despite the absence of detectable antibacterial activity under the experimental conditions used.