Sphingopyxis rigui sp. nov. and Sphingopyxis wooponensis sp. nov., isolated from wetland freshwater, and emended description of the genus Sphingopyxis

Abstract

Two yellow-pigmented, Gram-reaction-negative strains, designated 01SU5-PTand 03SU3-PT, were isolated from the freshwater of Woopo wetland, Republic of Korea. Both strains were aerobic, non-motile and catalase-negative. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates belong to the genusSphingopyxis, showing the highest level of sequence similarity with respect toSphingopyxis witflariensisW-50T(95.4–95.7 %). The two novel isolates shared 99.4 % sequence similarity. DNA–DNA hybridization between the isolates and the type strain ofS. witflariensisclearly suggested that strains 01SU5-PTand 03SU3-PTrepresent two separate novel species in the genusSphingopyxis. The two strains displayed different fingerprints after PCR analysis using the repetitive primers BOX, ERIC and REP. Several phenotypic characteristics served to differentiate these two isolates from recognized members of the genusSphingopyxis. The data from the polyphasic study presented here indicated that strains 01SU5-PTand 03SU3-PTshould be classified as representing novel species in the genusSphingopyxis, for which the namesSphingopyxis riguisp. nov. andSphingopyxis wooponensissp. nov., respectively, are proposed. The type strain ofSphingopyxis riguisp. nov. is 01SU5-PT( = KCTC 23326T = JCM 17509T) and the type strain ofSphingopyxis wooponensissp. nov. is 03SU3-PT( = KCTC 23340T = JCM 17547T).