Paenibacillus antarcticus sp nov., a novel psychrotolerant organism from the Antarctic environment

An endospore-forming strain, 20CM(T), was isolated from Antarctic sediment and identified as a member of the genus Paenibacillus on the basis of phenotypic and phylogenetic analyses. The organism stained Gram-variable and was facultatively anaerobic. Strain 20CM(T) was psychrotolerant, growing optimally at 10-15degreesC. Like other Paenibacillus species, it contained anteiso-C-15:0 as the major cellular fatty acid. The DNA G+C content was 40.7 mol%. 16S rRNA gene sequence analysis placed strain 20CMT within the Paenibacillus cluster, with a similarity value of 99.5% to Paenibacillus macquariensis DSM 2(T). DNA-DNA hybridization experiments between the Antarctic isolate and P. macquariensis DSM 2(T) revealed a reassociation value of 47%, indicating that strain 20CM(T) and P. macquariensis DSM 2(T) belong to different species. Based on evaluation of morphological, physiological, chemotaxonomic and phylogenetic analyses, a novel species, Paenibacillus antarcticus sp. nov., is proposed; the type strain is 20CM(T) ( = LMG 22078(T) = CECT 5836(T)).