Isolement et caractérisation des actinobactéries à partir d’un source thermale (station Hammam Bouhadjar ) et des deux sols salins et aride d’Algérie.

Abstract

After isolation, purification and enumeration of the actinobacteria, we carried out a pre- identification of the bacteria, based on cultural, morphological, physiological and biochemical characters. We then investigated the antimicrobial activity of these isolates against four pathogens and one mold. This study is completed by tolerance tests at different concentrations of NaCl and at different temperatures. A study on the sensitivity of acinobacteria to antibiotics was also undertaken. In total, 6 isolates of actinobacteria were isolated. During the purification, two isolates were contaminated, so only four isolates were purified and subjected to this modest work. The phenotypic characteristics of the isolates led us to relate them to the genus Streptomyces. The four isolates demonstrated significant antibiotic properties against pathogenic bacteria especially against the bacterium Pseudomonas aeroginosa. Tolerance to different concentrations of NaCl revealed that the four isolates tolerate and grow at these different concentrations tested. In terms of temperature, the isolates showed positive growth at 15, 25 and 30 ° C, but were inhibited at 5 ° C. The temperature 37 ° C was unfavorable to actinobacteria. The results of the antibiogram showed that the isolates react differently to the antibiotics tested, some were sensitive while others proved to be resistant. All of the actinobacterial isolates tested hydrolyzed gelatin, casein and starch except for human blood.