Geobacillus lituanicus sp. nov

Abstract

Obligately thermophilic, aerobic, proteolytic, endospore-forming strain N-3(T) was isolated from a high-temperature oilfield in Lithuania. 16S rRNA gene sequence analysis placed this strain in genetic group 5 of the endospore formers. Geobacillus thermoleovorans appeared to be the closest phylogenetic neighbour (99.4 % sequence similarity). The G+C content of strain N-3(T) was 52.5 mol% and matched the range established for the genus Geobacillus. Studies of DNA-DNA relatedness and morphological and physiological analyses enabled strain N-3(T) to be described as a member of the genus Geobacillus, but could not assign this strain to any other known species of this genus. Results of this polyphasic study allowed characterization of strain N-3(T) as a novel species in the genus Geobacillus - Geobacillus lituanicus sp. nov. This species can be distinguished from G. thermoleovorans and Geobacillus stearothermophilus on the basis of 16S rRNA gene PCR-RFLP assays with the restriction endonucleases AluI, HaeIII and TaqI. The type strain of the novel species is N-3(T) (=DSM 15325(T)=VKM B-2294(T)).