Carboxylicivirga gen. nov. in the family Marinilabiliaceae with two novel species, Carboxylicivirga mesophila sp. nov. and Carboxylicivirga taeanensis sp. nov., and reclassification of Cytophaga fermentans as Saccharicrinis fermentans gen. nov., comb. nov

Abstract

Two facultatively anaerobic mesophilic bacteria, strains MEBiC 07026T and MEBiC 08903T, were isolated from two different tidal flat sediments and both strains showed approximately 92.2 % 16S rRNA gene sequence similarity with [Cytophaga] fermentans DSM 9555T. 16S rRNA gene sequence similarity between the two new isolates was 97.5 % but levels of DNA-DNA relatedness between the two were 31.3-31.8 %. Phylogenetic analysis revealed that the two isolates and [Cytophaga] fermentans DSM 9555T were affiliated with the family Marinilabiliaceae in the class Bacteroidia. The dominant fatty acids of strains MEBiC 07026T, MEBiC 08903T and [Cytophaga] fermentans DSM 9555T were branched-type or hydroxylated C15: 0, but [Cytophaga] fermentans DSM 9555T contained a higher proportion of anteiso-branched fatty acids. The two new isolates contained a markedly higher proportion of monounsaturated fatty acids than other members of the family Marinilabiliaceae. The major respiratory quinone of the strains was MK-7. Strains MEBiC07026T and MEBiC08903T utilized a wide range of carboxylic acids whereas [Cytophaga] fermentans DSM 9555T utilized carbohydrates rather than carboxylic acids. The DNA G+C content of the novel strains was about 44 mol% but that of [Cytophaga] fermentans DSM 9555T revealed from the genome sequence was 37.6 mol%. Based on evidence from this polyphasic taxonomic study, a novel genus, Carboxylicivirga gen. nov., is proposed in the family Marinilabiliaceae with two novel species, Carboxylicivirga mesophila sp. nov. with type strain MEBiC 07026T (= KCCM 42978T = JCM 18290T) and Carboxylicivirga taeanensis sp. nov. with type strain MEBiC 08903T (= KCCM 43024T = JCM 19490T). Additionally, [Cytophaga] fermentans DSM 9555T (= ATCC 19072T) is reclassified as Saccharicrinis fermentans gen. nov., comb. nov. © 2014 IUMS.