Belliella baltica gen. nov., sp. nov., a novel marine bacterium of the Cytophaga–Flavobacterium–Bacteroides group isolated from surface water of the central Baltic Sea

Abstract

Two bacterial isolates from the Baltic Sea, BA1 and BA134T, were characterized for their physiological and biochemical features, fatty acid profiles and phylogenetic position based on 16S rRNA gene sequences. The strains were isolated from surface water of the central Baltic Sea during the decay of a plankton bloom. Phylogenetic analysis of their 16S rRNA gene sequences revealed a clear affiliation to the family ‘Flexibacteriaceae’ and showed highest sequence similarity (91 %) to Cyclobacterium marinum. The G+C content of the DNA was 35·4 mol%. The strains were pink-coloured due to carotinoids, Gram-negative, rod-shaped and catalase- and oxidase-positive. Growth was observed at 0–6 % salinity, with good growth at 0–3 %. Temperature for growth was 4–37 °C, with an optimum around 25 °C. The fatty acid profiles were dominated by branched-chain fatty acids (70 %), with a high abundance of iso-C15 : 0 (29–33 %), iso-C17 : 1 ω9c (7–10 %) and C17 : 1 ω6c (5–10 %). According to their morphology, physiology, fatty acid composition, 16S rRNA gene sequences and DNA–DNA similarity, on one hand, the described bacteria are considered to be members of the same novel species; on the other hand, they are suggested as a novel genus of the family ‘Flexibacteriaceae’. To honour the late aquatic microbiologist Russell T. Bell, the name Belliella baltica gen. nov, sp. nov. is suggested for the Baltic Sea isolates, for which the type strain is BA134T (=DSM 15883T=LMG 21964T=CIP 108006T).