Gilvimarinus polysaccharolyticus sp. nov., an agar-digesting bacterium isolated from seaweed, and emended description of the genus Gilvimarinus

Abstract

A taxonomic study was carried out on strain YN3T, which was isolated from a seaweed sample taken from the coast of Weihai, China. The bacterium was Gram-stain-negative, rod-shaped, and could grow at pH 5.0–10.0 and 4–32 °C in the presence of 0–9.0 % (w/v) NaCl. Strain YN3T was positive for the hydrolysis of polysaccharides, such as agar, starch and xylan. The predominant respiratory quinone was ubiquinone-8. The major fatty acids were C16 : 1ω7c and/or iso-C15 : 0 2-OH, C16 : 0 and C18 : 1ω7c. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, and two unidentified glycolipids. The genomic DNA G+C content was 49.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YN3T should be assigned to the genus Gilvimarinus . ‘Gilvimarinus agarilyticus’ KCTC 23325 and Gilvimarinus chinensis QM42T had the closest phylogenetic relationship to strain YN3T, and showed 97.9 % and 95.8 % sequence similarities, respectively. On the basis of phenotypic, chemotaxonomic and genotypic data and DNA–DNA hybridization studies, we propose that strain YN3T represents a novel species of the genus Gilvimarinus , for which the name Gilvimarinus polysaccharolyticus sp. nov. is proposed. The type strain is YN3T ( = KCTC 32438T = JCM 19198T). An emended description of the genus Gilvimarinus is also presented.