Novosphingobium umbonatum sp. nov., isolated from a freshwater mesocosm.

Abstract

A bacterial strain designated FSY-9T was isolated from a freshwater mesocosm in Taiwan and characterized to determine its taxonomic affiliation. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicated that strain FSY-9T formed a phylogenetic lineage in the genus Novosphingobium. Strain FSY-9T was most closely related to Novosphingobium humi R1-4T with a 97.2 % 16S rRNA gene sequence similarity. Strain FSY-9T showed 71.3-72.6 % average nucleotide identity and 17.7-23.0 % digital DNA-DNA hybridization identity with the strains of other Novosphingobium species. Cells of strain FSY-9T were facultatively anaerobic, Gram-negative, rod-shaped, non-motile and formed light yellow coloured colonies. Growth occurred at 15-37 °C and pH 5.5-7, and in the presence of 0-0.5 % NaCl. The major fatty acids (>10 %) of strain FSY-9T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C18 : 1ω7c and C16 : 0. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidyldimethylethanolamine, sphingoglycolipid, an uncharacterized aminophospholipid, an uncharacterized glycolipid and an uncharacterized lipid. The major polyamine was spermidine. The major isoprenoid quinone was Q-10. The DNA G+C content was 61.5 mol%. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain FSY-9T should be classified as a novel species of the genus Novosphingobium, for which the name Novosphingobium umbonatum sp. nov. is proposed. The type strain is FSY-9T (=BCRC 81052T=LMG 30054T=KCTC 52813T).