http://wjst.wu.ac.th Natural Sciences Diversity Analysis of an Extremely Acidic Soil in a Layer of Coal Mine Detected the Occurrence of Rare Actinobacteria Megga Ratnasari PIKOLI1,*, Irawan SUGORO2 and Suharti3 1Department of Biology, Faculty of Science and Technology, Universitas Islam Negeri Syarif Hidayatullah Jakarta, Ciputat, Tangerang Selatan, Indonesia 2Center for Application of Technology of Isotope and Radiation, Badan Tenaga Nuklir Nasional, Jakarta Selatan, Indonesia 3Department of Chemistry, Faculty of Science and Computation, Universitas Pertamina, Simprug, Jakarta Selatan, Indonesia (*Corresponding author’s e-mail:
[email protected],
[email protected]) Received: 7 September 2017, Revised: 11 September 2018, Accepted: 29 October 2018 Abstract Studies that explore the diversity of microorganisms in unusual (extreme) environments have become more common. Our research aims to predict the diversity of bacteria that inhabit an extreme environment, a coal mine’s soil with pH of 2.93. Soil samples were collected from the soil at a depth of 12 meters from the surface, which is a clay layer adjacent to a coal seam in Tanjung Enim, South Sumatera, Indonesia. A culture-independent method, the polymerase chain reaction based denaturing gradient gel electrophoresis, was used to amplify the 16S rRNA gene to detect the viable-but-unculturable bacteria. Results showed that some OTUs that have never been found in the coal environment and which have phylogenetic relationships to the rare actinobacteria Actinomadura, Actinoallomurus, Actinospica, Streptacidiphilus, Aciditerrimonas, and Ferrimicrobium. Accordingly, the highly acidic soil in the coal mine is a source of rare actinobacteria that can be explored further to obtain bioactive compounds for the benefit of biotechnology.