Sphingomonas degradans sp. nov. and Sphingomonas paludis sp. nov., isolated from the Han River and a wetland in South Korea.

Abstract

Two novel bacterial strains, designated CJ20T and CJ99T, belonging to the genus Sphingomonas, were isolated from the Han River in South Korea and a wetland in South Korea, respectively. Cells of both strains were Gram-stain-negative, aerobic, non-motile and yellow-pigmented. Strains were shown to grow optimally at 30˚C and pH 7 in the absence of NaCl on tryptic soy medium. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains CJ20T and CJ99T belonged to the genus Sphingomonas and were most closely related to S. asaccharolytica Y-345T and Sphingomonas koreensis JSS26T with 97.87% and 97.58% 16S rRNA gene sequence similarities, respectively. Average nucleotide identity and digital DNA-DNA hybridization values of strain CJ20T with S. asaccharolytica Y-345T were 74.1% and 15.9%, respectively and those values of strain CJ99T with S. koreensis JSS26T were 73.9% and 15.6%, respectively. Both strains contained ubiquinone (Q-10) as the predominant respiratory quinone. The major polar lipids of strains CJ20T and CJ99T comprised phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and sphingoglycolipid. The predominant fatty acids of both strains were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) and C16:0. Based on polyphasic taxonomic analyses, strains CJ20T and CJ99T represent novel species of the genus Sphingomonas, for which names Sphingomonas degradans sp. nov. and Sphingomonas paludis are proposed, respectively. The type strains are CJ20T (= KACC 23909 = JCM 37720) and CJ99T (= KACC 24077 = JCM 37956).