Isolation, Identification and Phylogeny of Actinobacteria from Island Soils Using Different Isolation Methods

Actinobacteria are one of the most frequently studied prokaryotic groups within the Bacteria domain. In this study, soil samples collected from the islands of Burgazada, Büyükada, Gökçeada, Heybeliada, and Kınalıada were used to isolate, identify, and analyze the phylogeny of Actinobacteria. For the isolation studies, three different isolation methods and 11 different selective media were employed. As a result, a total of 103 bacterial strains were isolated. The molecular identification of the isolated strains was conducted using 16S rRNA gene region sequence analyses. These analyses revealed that the isolates belonged to 12 different genera within the Actinobacteria phylum. Comparison of the 16S rRNA gene sequences of the isolates with their closest relatives in the EzBioCloud database indicated a sequence similarity ranging between 95.76% and 100%. The isolation studies demonstrated that the standard dilution plate method was more effective for isolating both diverse genera and potential novel species. The data obtained through this method showed that 22 of the isolated strains, belonging to 8 different genera, have the potential to represent novel species. In conclusion, this study highlights that island soils are an important source for the discovery of new Actinobacteria species. Furthermore, it emphasizes the significance of such isolation studies in uncovering the rich biotechnological potential of Actinobacteria.