Aequorivita gen. nov., a member of the family Flavobacteriaceae isolated from terrestrial and marine Antarctic habitats

Several strains isolated from Antarctic winter sea water, sea-ice algal assemblages and quartz stone subliths were found to belong to a novel 16S rDNA sequence cluster within the family Flavobacteriaceae (Cytophaga-Flavobacterium-Bacteroides division). The strains were Gram-negative, non-motile, psychrotolerant, strictly aerobic, chemoheterotrophic rod-shaped cells that contained orange or yellow carotenoid pigments and required yeast extract when grown in defined mineral-salts media. The requirement for sodium ions varied between strains. Results of DNA-DNA hybridization analysis were used to divide the strains into four distinct genospecies, which were differentiated by physiological and nutritional characteristics. The DNA G+C content of the strains was 33-39 mol%. The fatty acid profiles of representative strains were very similar, with major constituents including i15: 1ω10c, a15:1ω10c, i15:0, a15:0, i16:1ω6c, i17:1ω5c and 3-OH i16:0. The novel genus Aequorivita gen. nov., which has widespread distribution in the Antarctic region, is proposed. The genus comprises four species: the type species Aequorivita antarctica sp. nov. (type strain SW49T = ACAM 640T = DSM 14231T), Aequorivita lipolytica sp. nov. (type strain Y10-2T = ACAM 641T = DSM 14236T), Aequorivita crocea sp. nov. (type strain Y12-2T = ACAM 642T = DSM 14239T) and Aequorivita sublithincola sp. nov. (type strain 9-3T = ACAM 643T = DSM 14238T).