Flavobacterium chryseum sp nov and Flavobacterium psychroterrae sp nov., novel environmental bacteria isolated from Antarctica

A group of rod-shaped, aerobic, Gram-stain-negative, gliding bacteria producing flexirubin-type pigment was isolated from environmental samples collected in Antarctica in 2009-2014. Phylogenetic analysis of the almost complete 16S rRNA gene sequences revealed two separated branches belonging to the genus Flavobacterium. Group I (n=8), represented by strain CCM 8826(T), shared the highest sequence similarity to Flavobacterium collinsii 983-08(T) (98.8 %) and Flavobacterium saccharophilum DSM 1811(T) (98.4 %), and group II (n=4) represented by strain CCM 8827(T) shared the highest similarity to Flavobacterium aquidurense WB 1.1-56(T) (99.6 %). High genetic homogeneity of both groups, separation from each other and from phylogenetically close Flavobacterium species was verified by the rep-PCR fingerprinting method. DNA-DNA hybridization confirmed low genomic relatedness between strain CCM 8826(T) and F. collinsii 983-08(T) and F. saccharophilum DSM 1811(T) (18 and 28 %, respectively) and between strain CCM 8827(T) and F. aquidurense WB 1.1-56(T) (27%). Chemotaxonomic analyses of strains CCM 8826(T) and CCM 8827(T) revealed the respiratory quinone to be MK-6, the major identified polar lipid was phosphatidylethanolamine and the predominant polyamine was sym-homospermidine. The common major fatty acids were C-15:0 iso, C-17:0 iso 30H, C 15:1 iso G, Summed Feature 3 (C-16:1 omega 7c/C-16:1 omega 6c), C-15:0 iso 30H and additionally, C-15:0 anteiso among group II members. All analyses confirmed that strains of group I and II represent two novel species of the genus Flavobacterium, for which the names Flavobacterium chryseum sp. nov. (type strain CCM 8826(T)=P3160(T)=LMG 30615(T)) and Flavobacterium psychroterrae sp. nov. (type strain CCM 8827(T)=P3922(T)=LMG 30616(T)) are proposed.