Unveiling the Diversity and Biotechnological Potential of Halophilic Actinobacteria from the Sebkha of Lake Naïla, Morocco

Saline ecosystems, including saline lakes, are indeed major hotbeds of microbial novelty, harboring diverse and largely unexplored microbes. The sebkha of Lake Naïla (Morocco), an ecologically protected area registered under the Ramsar Convention in 1998, remains largely unexplored. Isolation using three different selective media enabled seven phenotypically distinct actinobacterial isolates to be obtained. Molecular characterization, based on 16S RNA gene sequencing, was used to identify strains as members of the genera Streptomyces, Nocardiopsis, and Prauserella. Three strains showed antimicrobial potential against pathogenic microorganisms, with Streptomyces sp. strain 43 exhibiting the most potent effects. Additionally, all isolates displayed plant-growth-promoting (PGP) traits, including phosphate solubilization, auxin (IAA) synthesis, siderophore secretion, and ammonia production. Notably, Nocardiopsis sp. strain 42 produced the highest IAA levels (282 μg/mL), while Streptomyces sp. strain 39, Streptomyces sp. strain 43, and Streptomyces sp. strain 48 excelled in phosphate solubilization. GC-MS profiling of Streptomyces sp. strain 43 revealed a complex metabolite repertoire, including 1,2-propanediol and nonanal, highlighting the strain’s versatile secondary metabolism. These findings highlight that the sebkha of Lake Naïla represents a rich source of halophilic actinobacteria with promising dual potential for antimicrobial and biofertilizer applications. The findings provide a solid basis for new perspectives on biotechnology applications and sustainable agriculture.