Shewanella waksmanii sp nov., isolated from a sipuncula (Phascolosoma japonicum)

Two marine bacterial strains, KMM 3823(T) and KMM 3836, isolated from a sipuncula (Phascolosoma japonicum), a common inhabitant of Troitsa Bay in the Gulf of Peter the Great (Sea of Japan), were studied. Comparative 16S rRNA gene sequence-based phylogenetic analysis placed these bacteria into a separate branch of the 'Gammaproteobacteria' within members of the genus Shewanella. KMM 3823 T showed the highest similarity (96.6%) with Shewanella fidelis. The DNA G + C contents of the two strains studied were 43.0 mol%. The level of DNA homology between these two strains was conspecific (93%), indicating that they represent a single genospecies. These organisms were greenish-brown, Gram-negative, polarly flagellated, facultatively anaerobic, mesophilic (temperature range 4-30 degreesC), neutrophilic, haemolytic and were able to degrade elastin, gelatin and DNA. They were susceptible to ampicillin, carbenicillin, gentamicin and kanamycin. The predominant fatty acids were characteristic for shewanellas: 13: 0-i, 15: 0-i and 16: 1 (n-7); up to 6-7% of eicosapentaenoic fatty acid, 20: 5(n-3), was produced during growth at 28 degreesC. Phylogenetic evidence, confirmed by DNA hybridization and phenotypic characteristics revealed that the two bacteria studied constitute a new species, Shewanella waksmanii sp. nov., the type strain of which is KMM 3823(T) (= CIP 107701(T) = ATCC BAA-643(T)).