Yakhlef, Wahiba2024-02-112024-02-112012http://dspace.univ-khenchela.dz:4000/handle/123456789/402Considerable interest is given to the thermophilic microorganisms associated with terrestrial hot springs. Sixteen microbial strains were isolated and purified from thermal water samples collected from hot springs in eastern Algeria. The samples in question are considered after measuring the temperature, as extreme ecosystems. Thermus medium (0.8% polypeptones, 0.4% yeast extract) was in favor of the isolation of aerobic thermophiles. It turned out that 50% of all isolates are thermophilc and 12.5% are hyperthermophilic. 18.75% of the isolates are able to grow in a pH range from 5 to 9. Four thermophilic strains were able to reduce nitrates; five are amylolytic, at least nine strains possess a proteolytic enzyme and four strains (28.57%) were active against at least one of the tests used bacteria (S. aureus ATCC 25923, S. aureus ATCC43300, P. aeruginosa ATCC25922 and E. coli ATCC27853). The study of their morphological, physiological and biochemical characters suggests that these strains belong to the genera Geobacillus, Pseudoxanthomonas, Aeromonas, Exiguobacterium, Thermus, Thermoproteus and Fervidobacterium. Our results extend our knowledge on the microbial communities indigenous to the hot springs and their interest in biotechnology.frThesis