Paracnuella aquatica gen. nov., sp. nov., a member of the family Chitinophagaceae isolated from a hot spring

A Gram-stain-negative, rod-shaped bacterium (designated strain N24 T ) with gliding motility was isolated from thermal spring water sampled at Xi'an, PR China. Cells were 0.4-0.8 µm wide and 1.8-7.8 µm long. Optimal growth occurred at 33 °C and pH 7.0 on Reasoner's 2A (R2A) agar. Strain N24 T could produce exopolysaccharide on R2A agar at 33 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain N24 T formed a distinct phyletic lineage within the family Chitinophagaceae and was most closely related to members of the genera Flavisolibacter, Cnuella, Niveitalea, Flavitalea, Flaviaesturariibacter and Niastella with 91.7-93.9 % 16S rRNA gene sequence similarities. The major fatty acids of strain N24 T were iso-C15 : 0 (31.8 %), iso-C17 : 0 3-OH (16.1 %) and iso-C15 : 1 G (12.9 %). The polar lipid profile consisted of phosphatidylethanolamine, two aminolipids and six unknown lipids; the quinone system consisted of menaquinone-7 (MK-7). The genomic G+C content was 49.3 mol%. On the basis of the evidence presented in this study, strain N24 T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Paracnuella aquatica gen. nov., sp. nov. is proposed. The type species is N24 T (=KCTC 62083 T =MCCC 1H00301 T ).