Full text loading...
Abstract
Five novel strains (2002T, 2902, 2006, 108T and 117) of cellulose-degrading, anaerobic, thermophilic bacteria were isolated from terrestrial hot springs of Kamchatka (Far East, Russia). Strains 2002T and 108T were non-spore-forming bacteria with a Gram-positive type cell wall and peritrichous flagella. Optimum growth of strains 2002T and 108T occurred at pH 7.0 and at temperatures of 70 and 65 °C, respectively. The G+C contents of the DNA of strains 2002T and 108T were 35.1 and 36.4 mol%, respectively. Comparative 16S rRNA gene sequence analysis revealed that the isolates belonged to the genus Caldicellulosiruptor. However, DNA–DNA hybridization experiments indicated that the levels of relatedness between strains 2002T and 108T and those of recognized members of the genus Caldicellulosiruptor ranged between 32 and 54 %. Based on both phenotypic and genomic differences, strains 2002T and 108T are considered to represent two novel species of the genus Caldicellulosiruptor. The names proposed for these organisms are Caldicellulosiruptor kronotskyensis sp. nov. (type strain 2002T=DSM 18902T=VKM B-2412T) and Caldicellulosiruptor hydrothermalis sp. nov. (type strain 108T=DSM 18901T=VKM B-2411T).
- Published Online: