Integrated Proteomic and Molecular Identification of Thermophilic Geobacillus Strains from Algerian Desert Sands and Their Enzymatic Potential

Thermophilic microorganisms are among the key natural sources of thermostable enzymes, found not only in geothermal areas but also in arid environments. In this study, eight Geobacillus strains were isolated from the arid sands of Aïn Sefra (Naâma, Algeria) and characterized both phenotypically and genetically. All strains exhibited an optimal growth temperature of 70 °C, with most showing alkaliphilic pH preferences. Proteomic and molecular analyses (MALDI-TOF MS, 16S rRNA) identified Geobacillus kaustophilus as predominant, with BOX-PCR and RAPD-PCR revealing notable intraspecies diversity. All strains synthesized at least one thermostable enzyme (protease, amylase, laccase, or DNase) at their optimal temperature (70 °C), positioning them as promising candidates for biotechnological processes requiring extreme thermal conditions.