Nubsella zeaxanthinifaciens gen. nov., sp. nov., a zeaxanthin-producing bacterium of the family Sphingobacteriaceae isolated from freshwater.

A yellow-pigmented, Gram-negative, strictly aerobic, rod-shaped bacterium (TDMA-5(T)) was isolated from a freshwater sample collected at Misasa (Tottori, Japan). The DNA G+C content was 38.6 mol%. Major fatty acids were iso-C(15 : 0), iso-C(17 : 0) 3-OH and summed feature 4 (iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c). MK-7 was the predominant respiratory quinone. Zeaxanthin was the major carotenoid pigment produced; flexirubin-type pigments were not produced. TDMA-5(T) was sensitive to gamma-irradiation. The strain degraded gelatin, casein, starch, Tween 80 and DNA. Phylogenetic analysis based on the 16S rRNA gene sequence placed TDMA-5(T) in a distinct lineage in the family Sphingobacteriaceae, sharing 89.4-93.4 % sequence similarity with members of the nearest genus Pedobacter. Strain TDMA-5(T) could be distinguished from the other members of the family Sphingobacteriaceae by a number of chemotaxonomic and phenotypic characteristics. Based on its unique phenotypic, genotypic and phylogenetic features, strain TDMA-5(T) represents a novel genus and species, for which the name Nubsella zeaxanthinifaciens gen. nov., sp. nov. is proposed. The type strain of Nubsella zeaxanthinifaciens is TDMA-5(T) (=NBRC 102579(T) =CCUG 54348(T)).