Abstract

Two novel Psychrobacter-like bacteria, strains KC 40(T) and KC 65, were isolated from a marine crustacean specimen collected from the Sea of Japan, and were characterized by using a polyphasic approach. Strains were selected on the basis of their ability to produce black-brown diffusible pigments on commonly used organic media, which appears to be a unique characteristic of recognized members of the genus Psychrobacter. Phylogenetic analyses based on both 16S rRNA and gyrB gene sequences showed that the novel isolates formed a separate cluster within the genus Psychrobacter. Strains KC 40(T) and KC 65 shared highest levels of 16S rRNA gene sequence similarity with Psychrobacter urativorans DSM 14009(T) (98.0 %), Psychrobacter pulmonis CCUG 46240(T) (97.9 %), Psychrobacter cibarius JG-219(T) (97.9 %), Psychrobacter faecalis Iso-46(T) (97.8 %), Psychrobacter aquimaris SW-210(T) (97.6 %), Psychrobacter namhaensis SW-242(T) (97.6 %) and Psychrobacter nivimaris 88/2-7(T) (97.6 %). DNA-DNA hybridization experiments revealed 84 % DNA-DNA relatedness between strains KC 40(T) and KC 65 but much lower levels of relatedness (7-35 %) between the novel strains and the type strains of recognized Psychrobacter species, confirming their assignment to a single novel species of the genus Psychrobacter. The two novel strains could be distinguished from recognized species of the genus Psychrobacter based on a combination of physiological and biochemical characteristics. On the basis of phenotypic and molecular properties, strains KC 40(T) and KC 65 are considered to represent a novel species of the genus Psychrobacter, for which the name Psychrobacter fulvigenes sp. nov. is proposed. The type strain is KC 40(T) (=KMM 3954(T)=NRIC 0746(T)=JCM 15525(T)).