Phenylobacterium muchangponense sp. nov., isolated from beach soil, and emended description of the genus Phenylobacterium

Abstract

A Gram-staining-negative, non-motile, aerobic bacterium, designated strain A8T, was isolated from the beach soil of Muchangpo, Korea. Cells were rod-shaped (0.5–0.6×0.7–1.3 µm) and colonies were colourless, circular with entire edges and had a glistening surface. The isolate grew optimally at 25–35 °C and did not require NaCl for growth. Strain A8T could not assimilate acetate, dl-lactate, succinate, antipyrine or chloridazon, but weakly assimilated l-phenylalanine. Major fatty acids were summed feature 7 (comprising C18 : 1ω7c/ω9t/ω12t), C16 : 0 and summed feature 4 (comprising C16 : 1ω7c/ iso-C15 : 0 2-OH). The major isoprenoid quinone was ubiquinone-10 and the DNA G+C content was 72.3 mol%. Comparative 16S rRNA gene sequence studies showed that strain A8T belonged to the family Caulobacteraceae , class Alphaproteobacteria and was most closely related to type strains of members of the genus Phenylobacterium (95.7–97.1 % similarity). Signature nucleotides and phylogenetic analysis of the 16S rRNA gene sequence also suggested that strain A8T was affiliated with the genus Phenylobacterium . Low DNA–DNA relatedness values (3.0±1.8–11.5±3.2 %) indicated that strain A8T represented a distinct species that was separated from other type strains in the genus Phenylobacterium . On the basis of evidence from a polyphasic study, it is proposed that strain A8T ( = KACC 15042T  = LMG 25973T) represents the type strain of a novel species, Phenylobacterium muchangponense sp. nov. An emended description of the genus Phenylobacterium is also presented.