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

A Gram-staining-negative, non-motile, aerobic bacterium, designated strain A8(T), was isolated from the beach soil of Muchangpo, Korea. Cells were rod-shaped (0.5-0.6x0.7-1.3 mu m) and colonies were colourless, circular with entire edges and had a glistening surface. The isolate grew optimally at 25-35 degrees C and did not require NaCI for growth. Strain A8(T) could not assimilate acetate, DL-lactate, succinate, antipyrine or chloridazon, but weakly assimilated L-phenylalanine. Major fatty acids were summed feature 7 (comprising C-18:1 omega 7c/omega 9t/omega 12t), C-16:0 and summed feature 4 (comprising C-16:1 omega 7c/ iso-C-15:0 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 A8(T) 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 A8(T) was affiliated with the genus Phenylobacterium. Low DNA DNA relatedness values (3.0 +/- 1.8-11.5 +/- 3.2%) indicated that strain A8(T) 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 A8(T) (=KACC 15042(T) =LMG 25973(T)) represents the type strain of a novel species, Phenylobacterium muchangponense sp. nov. An emended description of the genus Phenylobacterium is also presented.