Sphingomonas spermidinifaciens sp. nov., a novel bacterium containing spermidine as the major polyamine, isolated from an abandoned lead-zinc mine and emended descriptions of the genus Sphingomonas and the species Sphingomonas yantingensis and Sphingomonas japonica.

A yellow-pigmented bacterial strain, designated 9NM-10T, was isolated from an abandoned lead-zinc mine in Meizhou, Guangdong Province, China. Cells were strictly aerobic, Gram-stain-negative and motile with a polar monotrichous flagellum. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain 9NM-10T belongs to the genus Sphingomonas and was most closely related to Sphingomonas yantingensis JCM 19201T and Sphingomonas japonica JCM 15438T. DNA-DNA relatedness values between strain 9NM-10T and these two type strains were 43.6±1.3 and 35.4±0.9 %, respectively. It contained Q-10 as the predominant respiratory quinone and the major cellular fatty acids were C18 : 1ω7c, C16 : 0, C17 : 1ω6c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The genomic DNA G+C content of strain 9NM-10T was 68.7±0.2 mol%. The polar lipids were sphingoglycolipid, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol, an unidentified phospholipid and three unidentified lipids. Strain 9NM-10T contained spermidine as the major polyamine. On the basis of phenotypic, phylogenetic and chemotaxonomic analyses, strain 9NM-10T is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas spermidinifaciens sp. nov. is proposed. The type strain is 9NM-10T (=GDMCC 1.657T=DSM 27571T). Descriptions of the genus of Sphingomonas and the species Sphingomonas yantingensis and Sphingomonas japonica were also emended in this study.