Isolation and 16S rRNA gene sequences analysis of thermophilic Actinobacteria isolated from soil in Cisolok geothermal area, West Java, Indonesia

Abstract

The thermophilic Actinobacteria are known not only as producers of pharmaceutically important bioactive compounds, but also commercially important enzymes, yet their diversity in geothermal area in Indonesia have been rarely reported. In our previous study, a new thermophilic Actinobacteria genus belonging to the family Pseudonocardiaceae has been isolated from soil in Cisolok geothermal area. This current study reports the taxonomy and findings of potentially new taxa of thermophilic Actinobacteria, based on phylogenetic analysis of 16S rRNA gene sequences. Twenty-five isolates of thermophilic Actinobacteria were isolated from soil samples and maintained using previously described methods. The 16S rRNA gene sequence-similarity search against all related species was performed using EzTaxon-e database. The sequences of 25 isolates showed similarity to member of family Streptomycetaceae (genus Streptomyces; 10 isolates), Thermomonosporaceae (genus Actinomadura; 3 isolates), Streptosporangiaceae (genus Microbispora; 6 isolates), Micromonosporaceae (genus Micromonospora; 2 isolates), Pseudonocardiaceae (genus Amycolatopsis; 3 isolates), and Nocardiaceae (genus Nocardia; 1 isolate). Fifteen out of 25 isolates are belong to non-Streptomycetaceae family, thus regarded as rare Actinobacteria. Nineteen out of 25 isolates showed 16S rRNA gene sequence-similarity values 97 – 99% to their closely related species, suggested the potential for findings novel taxa of thermophilic Actinobacteria from Cisolok geothermal area.