Sphingobium lactosutens sp. nov., isolated from a hexachlorocyclohexane dump site and Sphingobium abikonense sp. nov., isolated from oil-contaminated soil.

The taxonomic position of a yellow-pigmented bacterial strain, designated DS20T, isolated from a hexachlorocyclohexane dump site at Lucknow, India was determined based on a polyphasic taxonomic characterization. A neighbour-joining tree based on 16S rRNA gene sequences showed that strain DS20T occupied a distinct phylogenetic position in the Sphingobium cluster, showing highest similarity with 'Pseudomonas abikonensis' IAM 12404 (98.8%), followed by Sphingobium rhizovicinum CC-FH12-1T (97.4%) and Sphingobium olei IMMIB HF-1T (97.2%). Therefore, the taxonomic characterization of 'P. abikonensis' NBRC 16140 was also undertaken. Phylogenetic, chemotaxonomic and morphological analyses, based on signature sequences, DNA-DNA hybridizations, fatty acid profiles, physiological characterizations and polar lipid profiles confirmed that both strains DS20T and 'P. abikonensis' NBRC 16140 represent two distinct species of the genus Sphingobium. Therefore, two novel Sphingobium species are proposed, Sphingobium lactosutens sp. nov. (type strain, DS20T=CCM 7540T=MTCC 9471T) and Sphingobium abikonense sp. nov. (type strain, NBRC 16140T=IAM 12404T=KCTC 2864T).