Oceanobacillus oncorhynchi sp. nov., a halotolerant obligate alkaliphile isolated from the skin of a rainbow trout (Oncorhynchus mykiss), and emended description of the genus Oceanobacillus.

A halotolerant, obligately alkaliphilic bacterium, R-2(T), was isolated from the skin of a rainbow trout (Oncorhynchus mykiss), a freshwater fish. The strain is Gram-positive, ferments several carbohydrates, is rod-shaped and motile by peritrichous flagella and produces ellipsoidal spores. The isolate grows at pH 9-10 but not at pH 7-8. This micro-organism grows in 0-22% (w/v) NaCl at pH 10. Its major cellular fatty acids are iso-C(15:0), anteiso-C(15:0) and anteiso-C(17:0), the major isoprenoid quinone is MK-7 and the DNA G+C content is 38.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicates that strain R-2(T) is a member of the genus Oceanobacillus. DNA-DNA hybridization reveals low relatedness between the isolate and Oceanobacillus iheyensis (21.0%). On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA relatedness data, the isolate should be designated as a novel species, for which the name Oceanobacillus oncorhynchi sp. nov. is proposed. The type strain is R-2(T) (=JCM 12661(T)=NCIMB 14022(T)).