Porphyrobacter algicida sp. nov., an algalytic bacterium isolated from seawater

A novel Gram-stain-negative, yellow-pigmented, catalase- and oxidase-positive, non-endospore-forming, flagellated bacterium, designated strain Yeonmyeong 2-22^T, was isolated from surface seawater of Geoje Island, Republic of Korea. Strain Yeonmyeong 2-22^T showed algalytic activity against the seven strains tested: Cochlodinium polykrikoides, Chattonella marina, Heterosigma akashiwo, Scrippsiella trochoidea, Heterocapsa triquetra, Prorocentrum minimum and Skeletonema costatum. A taxonomic study was carried out based on a polyphasic approach to characterize the exact taxonomic position of strain Yeonmyeong 2-22^T. The bacterium was able to grow at 10–40 °C, at salinities from 0 to 9%, at pH from 4.0 to 9.0 and was not able to degrade gelatin or casein. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain Yeonmyeong 2-22^T was considered to represent a novel species of the genus Porphyrobacter, which belongs to the family Erythrobacteraceae, and was related most closely to Porphyrobacter dokdonensis DSW-74^T with 97.23% 16S rRNA gene sequence similarity. The dominant cellular fatty acids of strain Yeonmyeong 2-22^T were C_{18: 1}ω7c (49.7%), C_{16: 0} (12.0%) and 11-methyl C_{18: 1}ω7c (11.5%), and ubiquinone-10 (Q-10) was the predominant respiratory lipoquinone. The genomic DNA G+C content of strain Yeonmyeong 2-22^T was calculated to be 63.0 mol%. Phenotypic characteristics of the novel strain also differed from other members of the genus Porphyrobacter. On the basis of polyphasic taxonomic data, strain Yeonmyeong 2-22^Trepresents as a novel species of the genus Porphyrobacter, for which the name of Porphyrobacter algicida sp. nov. is proposed. The type strain is Yeonmyeong 2-22^T (=KEMB 9005-328^T=JCM 31499^T).