In this paper, a new bacterial strain designated as 16MFT21T is isolated from the muscle of a fish caught in the Antarctic Ocean. Strain 16MFT21T is a Gram-staining-positive, catalase-oxidase-positive, rod-shaped facultative-aerobic bacterium. The phylogenetic analysis that is based on the 16S-rRNA gene sequence of strain 16MFT21T revealed that it belongs to the genus Bacillus in the family Bacillaceae in the class Bacilli. The highest degrees of the sequence similarity of the strain 16MFT21T is with Bacillus licheniformis ATCC 14580T (96.6%) and Bacillus sonorensis NBRC 101234T (96.6%). The isolate formed a pale-yellow pigment, and it grew in the presence of 0% to 10% (w/v) NaCl (optimum at 2% NaCl), a pH of 6.0 to 10.0 (optimum pH from 7.0 to 8.0), and from 4°C to 30°C (optimum at 30°C). The major polar lipids consist of diphosphatidylglycerol (DPG) and phosphatidylglycerol (PG). The predominant fatty acids are iso-C15:0, anteiso-C15:0, iso-C17:0, and anteiso-C17:0. The main respiratory quinone is menaquinone-7 (MK-7), and based on the use of the meso-diaminopimelic acid as the diagnostic diamino acid, the peptidoglycan cell-wall type is A1γ. Based on the phylogenetic, phenotypic, and chemotaxonomic data, strain 16MFT21T (=KCTC 18866T =JCM 31664T) for which the name Bacillus piscis sp. nov. is proposed should be classified as a new species.
Keywords: Antarctic Ocean; Antarctic toothfish; Bacillus; Dissostichus mawsoni; taxonomy.