Photobacterium lipolyticum sp. nov., a bacterium with lipolytic activity isolated from the Yellow Sea in Korea

Abstract

A Gram-negative, motile, non-spore-forming, pleomorphic and lipolytic bacterial strain, M37T, was isolated from an intertidal sediment of the Yellow Sea in Korea. This organism grew optimally at 25-28 °C and in the presence of 1-2% NaCl. It did not grow without NaCl or in the presence of more than 6% NaCl. Strain M37T was characterized chemotaxonomically by having Q-8 as the predominant respiratory lipoquinone and C16:1ω7c and/or iso-C15:0 2-OH and C16:0 as the major fatty acids. The DNA G+C content was 47 mol%. Phylogenetic analyses based on 16S RNA gene sequences placed strain M37T within the clade comprising Photobacterium species, forming a coherent cluster with the type strains of Photobacterium profundum and Photobacterium indicum (16S rRNA gene similarity levels of 97.5-98.0%). The mean DNA-DNA relatedness levels between strain M37T and P. profundum JCM 10084T and P. indicum DSM 5151T were in the range 12-15%. Similarities between 16S RNA gene sequences of strain M37T and those of the type strains of the other Photobacterium species ranged from 93.9% (with Photobacterium fischeri) to 96.2% (with Photobacterium phosphoreum). On the basis of phenotypic properties and phylogenetic and genomic distinctiveness, strain M37T (=KCTC 10562BPT=DSM 16190T) should be placed in the genus Photobacterium as a novel species, for which the name Photobacterium lipolyticum sp. nov. is proposed.