Chitinirhabdus sediminis gen. nov. sp. nov., a novel chitin-degrading bacterium of family Chitinibacteraceae isolated from the mangrove sediment

A novel bacterial strain with chitin-degrading ability, designated strain HSL-7 T , was isolated from a mangrove sediment in Guangxi, PR China. Cells of strain HSL-7 T were Gram-stain-positive, aerobic, rod-shaped bacteria with a single polar flagellum. The strain grew at concentrations of 0–1% (w/v) NaCl (optimum at 0.5%), at pH 6.0–10.0 (optimum at 7.0) and in a temperature range of 15–37 °C (optimum at 20 °C). Strain HSL-7 T shared the highest 16S rRNA gene sequence percentage with Chitinibacter tainanensis BCRC 17254 T (94.4%). Phylogenetic analyses based on 16S rRNA gene and genome sequences showed that strain HSL-7 T formed a distinct cluster in the family Chitinibacteraceae . The genome-relatedness indices between strain HSL-7 T and other type species of the family Chitinibacteraceae were in the ranges of 75.61–79.73% for average nucleotide identity, 65.50–70.65% for average amino acid identity and 12.7–17.4% for digital DNA–DNA hybridization, which were significantly below the cut-off values for the genus delineation. The genome comprised 3,144,197 bp with a genomic DNA G+C content of 61.5 mol%. The major isoprenoid quinone was ubiquinone-8. The predominant fatty acids were summed feature 3 (C 16:1 ω 6c and/or C 16:1 ω 7c ), summed feature 8 (C 18:1 ω 7c and/or C 18:1 ω 6c ) and C 16:0 . The polar lipids comprised aminolipid, aminophospholipid, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipid and an unidentified lipid. The polyphasic taxonomic properties indicated that the strain represents a novel genus and species in the family Chitinibacteraceae for which the name Chitinirhabdus sediminis gen. nov., sp. nov. is proposed. The type strain is HSL-7 T (=JCM 37906 T =MCCC 1K09933 T ).