Isolation and characterization of thermophilic bacterial strains from Soldhar (Tapovan) hot spring in Central Himalayan Region, India

In the present investigation, 11 morphologically distinct thermophilic bacterial strains have been isolated from the Soldhar hot spring site in the Garhwal region of the Indian Himalaya. The phenotypic and genotypic characters of the isolates were studied using standards methods. All of them developed circular colonies on Tryptone Soy agar plates at 70 °C following 24 h incubation. The isolates grew over a wide range of temperatures (20–100 °C) and pHs (5–10). The cell morphology varied from short to long rods and cocci with a dominance of Gram-positive bacteria. The isolates exhibited varied biochemical properties with regard to the production of various enzymes and capability to ferment sugars. Based on restriction digestion with HaeIII, six phylogenetic groups were formed. Two isolates were selected for 16S rRNA gene sequence analysis, and exhibited maximum similarity and closest homology with Geobacillus thermocatenulatus and Geobacillus thermoleovorans, respectively.