Paraflavisolibacter caeni gen. nov., sp. nov., a novel taxon within the family Chitinophagaceae isolated from sludge.

A Gram-stain-negative bacterium, designated strain LB-8T, was isolated from an activated sludge sample collected from a factory in Binzhou city, Shandong province, PR China. Cells of strain LB-8T were strictly aerobic, non-motile and rod-shaped. Growth occurred at 15-40 °C (optimum, 30 °C), at pH 6.0-9.0 (optimum, pH 7.0) and at 0-7.5 % (w/v) NaCl (optimum, 0.5 % NaCl). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LB-8T formed a distinct phyletic branch within the family Chitinophagaceae and was most closely related to members of the genera Flavisolibacter, Cnuella and Paracnuella with 92.7-93.3 % 16S rRNA gene sequence similarities. The average amino acid identity values between strain LB-8T and its closed phylogenetic neighbours Flavisolibacter, Cnuella and Paracnuella were below 70 % supporting that strain LB-8T was a member of a novel genus. The predominant cellular fatty acids of LB-8T were iso-C15 : 0, anteiso-C15 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and iso-C17 : 0 3-OH, and the only isoprenoid quinone was menaquinone-7 (MK-7). The major polar lipids of strain LB-8T were phosphatidylethanolamine, four unidentified aminolipids and two unidentified lipids. The genome size of strain LB-8T was 7.01 Mbp with 41.2 mol% G+C content. On the basis of the evidence presented in this study, strain LB-8T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Paraflavisolibacter caeni gen. nov., sp. nov. (type strain LB-8T=GDMCC 1.3631T=KCTC 92688T) is proposed.