Diversity of Hyperthermophililic Bacteria Belonging to order Thermotogales Thriving in Three Hot Springs in Thailand: Resources of Genes Encoding Thermostable Enzymes

Abstract

Hyperthermophilic microorganisms belonging to order Thermotogales and thriving in high temperature habitats grow at temperatures above 70 to near 100 o C. In this study, 15 rod shaped bacteria with characteristic of terminal sac-like membrane were isolated from Pong Duet, Fang, and Jae Son hot springs. Differential biochemical properties of the isolates were characterized. Twelve isolates were detected utilizing carbohydrates in CT basal medium, but no growth was observed in the other three isolates. Keratin in native duck feather was degraded at 75-80 o C by 8 isolates. Based on morphology, physiology, and 16S rDNA sequences, 5 and 10 isolates belonging to morphological groups I and II were identified as Thermotoga species and Fervidobacterium species, respectively. The 16S rDNA type II PCR profile of the isolates FC2004, FC201, FC202, FA004 and JS602 distinguish themselves from previously reported known species belonging to Fervidobacterium . Results obtained from this study indicate that some Thailand’s isolates are distinct, and the geothermal spring ecosystems are rich in divergent hyperthermophiles which still remain to be explored. The hyperthermophilic isolates are crucial sources of numerous thermostable enzymes with potential to be applicable in the degradation of polymers in agricultural wastes such as starch, cellulose, and keratin. Key words: hot spring ; hyperthermophile; Thermotogales ; thermostable enzyme