New Thermophilic Thermobifida Strain Kb-T3 From Algerian Saharan Soil: Isolation and Polyphasic Taxonomy

Abstract

During a screening for the diversity of actinobacterial strains from Saharan soil samples collected from Béchar region (Algeria), one strain designated KB-T3 was isolated by dilution technique on chitin-vitamins agar medium. The taxonomic position of this strain was determined by using a polyphasic approach. Morphological and chemical characteristics of the KB-T3 strain were consistent with those of the genus Thermobifida. The KB-T3 strain had a white aerial mycelium with dictomically branched sporophores carrying coccoid secluded spores. The substrate mycelium was pale yellow, sterile, and non-fragmented. The strain is characterized by the presence of meso-diaminopimelic acid in the cell wall, the galactose in whole-cell, and phosphatidylethanolamine in the cell membrane. The unique characteristic of this strain was its abundant growth with the absence of NaCl and in temperature‎ ranging from 40 to 65 °C, its capacity to decompose acetate, and its ability to use fructose, glucose and xylose as sole carbon source. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strain KB-T3 should be classified in the genus Thermobifida and exhibited 99.79 % gene sequence similarity to Thermobifida fusca NBRC 14071T.