Sphingomonas turrisvirgatae sp. nov., an agar-degrading species isolated from freshwater

A yellow pigmented and agar-pitting colony was isolated from a water sample obtained from a drainage ditch within a disused system of constructed wetlands. The strain was purified and named MCT13^T. This rod-shaped, Gram-negative, oxidase- and catalase-positive, aerobic, non-spore-forming, and non-motile strain formed round colonies and grew optimally at pH 7.5±0.2, at 28-30 °C on LB agar, with 0-0.5 % NaCl. The 16S rRNA gene sequence analysis placed the MCT13^T isolate within the Sphingomonas (sensu stricto) cluster. The DNA G+C content was 65.3 %. The only observed ubiquinone was Q10. The major fatty acids included C17 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. The major polar lipids were sphingoglycolipid, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The major polyamine was spermidine. The 16S rRNA gene phylogenetic analysis performed on the whole sequence, showed the closest relative of MCT13^T to be Sphingomonas koreensis (98.52 %); however, there are several genotypic and phenotypic differences between the novel isolate and the type strain JSS26^T of S. koreensis. On the basis of these results, strain MCT13^T represents a novel species in the genus Sphingomonas, for which the name Sphingomonas turrisvirgatae sp. nov. is proposed. The type strain is MCT13^T (=DSM 105457^T=BAC RE RSCIC 7^T).