Psychrobacillus glaciei sp. nov., a psychrotolerant species isolated from an Antarctic iceberg.

Abstract

We performed taxonomic studies on a psychrotolerant strain, designated PB01T, isolated from an Antarctic iceberg. The cells of strain PB01T were Gram-stain-positive, strictly aerobic, white-yellow and rod-shaped. The results of 16S rRNA gene sequence analysis revealed that strain PB01T was closely related to Psychrobacillus psychrodurans DSM 11713T (99.19 % similarity), Psychrobacillus psychrotolerans DSM 11706T (98.91 %) and Psychrobacillus insolitus DSM 5T (98.85 %). Despite high 16S rRNA gene sequence similarity, the degrees of DNA-DNA relatedness between strain PB01T and its three closest phylogenetic neighbours were 62.4±7.3 % for P. psychrodurans DSM 11713T, 61.1±5.4 % for P. psychrotolerans DSM 11706T and 56.1±6.9 % for P. insolitus DSM 5T. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and C16 : 1ω7с-OH. Menaquinone-8 was the major respiratory quinone, and phosphatidylethanolamine was the major polar lipid. The DNA G+C content of strain PB01T calculated from the complete genome sequence was 36.0 mol%. Based on the phenotypic, chemotaxonomic, genomic and phylogenetic data obtained in the present study, we conclude that strain PB01T represents a novel species of the genus Psychrobacillus, for which we propose the name Psychrobacillus glaciei sp. nov. The type strain is PB01T (=CECT 9792T=KCTC 43041T).