Flavobacterium degerlachei sp. nov., Flavobacterium frigoris sp. nov. and Flavobacterium micromati sp. nov., novel psychrophilic bacteria isolated from microbial mats in Antarctic lakes.

Taxonomic studies were performed on 36 strains that were isolated from microbial mats in Antarctic lakes of the Vestfold Hills, the Larsemann Hills and the McMurdo Dry Valleys. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains are related to members of the genus Flavobacterium; sequence similarity values with their nearest phylogenetic neighbours ranged from 96.8 to 98.5%. Results of DNA-DNA hybridization and comparison of repetitive extragenic palindromic DNA-PCR fingerprinting patterns revealed that these strains are members of three distinct species. Genotypic results, together with phenotypic characteristics, allowed the differentiation of these species from related Flavobacterium species with validly published names. The isolates are Gram-negative, chemoheterotrophic, rod-shaped cells that are psychrophilic and moderately halotolerant; their DNA G+C contents range from 33.1 to 34.5 mol%. Their whole-cell fatty acid profiles are similar and include C(15:0), anteiso-C(15:0), iso-C(15:0), C(15:1)omega6c, iso-C(16:0), iso-C(16:0) 3-OH and summed feature 3 (which comprises iso-C(15:0) 2-OH, C(16:1)omega7c or both) as major fatty acid components. On the basis of these results, three novel species are proposed, namely Flavobacterium degerlachei sp. nov. (consisting of 14 strains, with LMG 21915T=DSM 15718T as the type strain), Flavobacterium micromati sp. nov. (consisting of three strains, with LMG 21919T=CIP 108161T as the type strain) and Flavobacterium frigoris sp. nov. (consisting of 19 strains, with LMG 21922T=DSM 15719T as the type strain).