Sphingomonas indica sp. nov., isolated from hexachlorocyclohexane (HCH)-contaminated soil

A bacterial strain, designated Dd16(T), was isolated from a hexachlorocyclohexane (HCH) dumpsite at Lucknow, India. Cells of strain Dd16(T) were Gram-stain-negative, non-motile, rod-shaped and yellow-pigmented. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain belonged to the genus Sphingomonas in the family Sphingomonadaceae, as it showed highest sequence similarity to Sphingomonas asaccharolytica IFO 15499(T) (95.36 %), Sphingosinicella vermicomposti YC7378(T) (95.30), 'Sphingomonas humi' PB323 (95.20 %), Sphingomonas sanxanigenens NX02(T) (95.14%) and Sphingomonas desiccabilis CP1D(T) (95.00%). The major fatty acids were summed feature 3 (C(16:1)ω7c/C(16:1)ω6c) C(14:0) 2-OH, summed feature 8 (C(18:1)ω7c and/or C(18:1)ω6c) and C(16:0). The polar lipid profile of strain Dd16(T) also corresponded to those reported for species of the genus Sphingomonas (phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, and a sphingoglycolipid), again supporting its identification as a member of the genus Sphingomonas. The predominant respiratory quinone was ubiquinone Q(10), and sym-homospermidine was the major polyamine observed. The total DNA G+C content of strain Dd16(T) was 65.8 mol%. The results obtained on the basis of phenotypic characteristics and phylogenetic analysis and after biochemical and physiological tests, clearly distinguished strain Dd16(T) from closely related members of the genus Sphingomonas. Thus, strain Dd16(T) represents a novel species of the genus Sphingomonas for which the name Sphingomonas indica sp. nov. is proposed. The type strain is Dd16(T) ( = DSM 25434(T)  = CCM 7882(T)).