Krokinobacter gen. nov., with three novel species, in the family Flavobacteriaceae

Abstract

Five strains belonging to the family Flavobacteriaceae were isolated from marine-sediment samples collected in Sagami and Tokyo bays on the Pacific coastline of Japan. The five isolates formed a coherent and novel genus-level lineage within the family Flavobacteriaceae. The most closely related species with a validly published name was Cellulophaga lytica. The five isolates were rod-shaped, Gram-negative, aerobic, catalase- and oxidase-positive, flexirubin-negative and yellow-pigmented. The dominant fatty acids were branched or hydroxy acids, i.e. i-C15 : 0, i-C15 : 1 and i-C17 : 0 3-OH. These strains degraded gelatin, casein, DNA and Tween 80. The G+C content of their DNAs ranged between 33 and 39 mol%. Although analysis of the 16S rRNA gene sequence similarity divided these strains into two subgroups with a 2·3 % sequence difference, the results of DNA–DNA hybridization indicated the grouping of these strains into three distinct species. On the basis of phenotypic and genotypic analyses, the novel genus Krokinobacter is proposed, with Krokinobacter genikus sp. nov., containing three of the strains, as the type species. The type strain is Cos-13T (=NBRC 100811T=CIP 108744T). The names Krokinobacter eikastus sp. nov. (type strain PMA-26T=NBRC 100814T=CIP 108743T) and Krokinobacter diaphorus sp. nov. (type strain MSKK-32T=NBRC 100817T=CIP 108745T) are proposed for the other two isolates.