Allohahella marinimesophila gen. nov., sp. nov., isolated from seawater and reclassification of Hahella antarctica as Allohahella antarctica comb. nov.

A Gram-stain-negative, non-endospore-forming, strictly aerobic, irregular rod-shaped bacterium without flagellum, designated strain H94T, was isolated by the high-throughput cultivation method from seawater of an amphioxus breeding zone in the coastal region of Qingdao, China. Growth was observed at 4-37 °C (optimum 28 °C), at pH 6.0-10.0 (optimum pH 7.0) and in the presence of 1-12 % (w/v) NaCl (optimum 1-2 %). The predominant cellular fatty acids were C18 : 1ω9c, C16 : 0 and C16 : 1ω9c. The polar lipids comprised phosphatidylethanolamine, phosphatidylglycerol and an unidentified phosphoglycolipid. The major respiratory quinone was ubiquinone-9 (Q-9). The genomic DNA G+C content of strain H94T was 56.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain H94T shared the highest similarity (95.9 %) with Hahella antarctica NBRC 102683T, and exhibited 92.9 % and 92.1 % similarity with the two other recognized Hahella species, Hahella chejuensis KCTC 2396T and Hahella ganghwensis DSM 17046T, respectively. The phylogenetic position revealed that strain H94T formed a stable distinct lineage cluster together with Hahella antarctica NBRC 102683T and this result was further confirmed by multilocus sequence analysis based on housekeeping genes gyrB and rpoB. On the basis of the polyphasic taxonomic analyses, strain H94T is considered to represent a novel species in a new genus, for which the name Allohahellamarinimesophila gen. nov., sp. nov. is proposed. The type strain of Allohahellamarinimesophila is H94T (=CGMCC 1.10800T=JCM 17555T). It is also proposed that Hahella antarctica should be reclassified within the genus Allohahella as Allohahella antarctica comb. nov. (type strain NBRC 102683T=IMCC 3113T=KCCM 42675T). The type species of the genus Allohahella is Allohahella antarctica comb. nov.