On the basis of phenotypic and genotypic characteristics and 16S rDNA sequence analysis, a novel species belonging to the genus Pseudomonas sensu stricto was identified. The saprophytic, fluorescent bacterium, designated KMM 3447(T), was isolated from a drinking water reservoir near Vladivostok City, Russia. The novel organism was a Gram-negative, aerobic, rod-shaped bacterium that produced a cyclic depsipeptide with surface-active properties. It degraded casein, but did not degrade gelatin, starch, agar or Tween 80. The bacterium was also haemolytic. Growth of the novel bacterium occurred between 4 and 35 degrees C. The predominant cellular fatty acids of the novel pseudomonad were C(16:0), C(16:1(n-7)), C(18:1(n-7)) and C(17:0 cyclo); branched fatty acids were only found in trace amounts. The G+C content of the novel bacterium was 61.0 mol%. 16S rDNA sequence analysis indicated that the novel bacterium had a clear affiliation with Pseudomonas fluorescens and species closely related to this recognized pseudomonad. DNA--DNA hybridization experiments showed that the novel bacterium bound at low levels (27--53%) with the DNA of the type strains of its nearest phylogenetic relatives, namely Pseudomonas tolaasii, Pseudomonas veronii, Pseudomonas orientalis and Pseudomonas rhodesiae, indicating that the novel bacterium represented a novel species within the genus Pseudomonas, for which the name Pseudomonas extremorientalis is proposed; the type strain is KMM 3447(T) (=LMG 19695(T)).