Sphingobium ummariense sp. nov., a hexachlorocyclohexane (HCH)-degrading bacterium, isolated from HCH-contaminated soil.

A hexachlorocyclohexane (HCH)-degrading bacterial strain (RL-3T) was isolated from an HCH dump site located in the northern part of India. Resting cell assays and analytical GC studies confirmed the ability of strain RL-3T to degrade HCH isomers. Southern blot hybridization studies revealed the presence of lin genes, which are involved in the HCH degradation pathway, in this bacterium. The 16S rRNA gene sequence of strain RL-3T showed that it was most closely related to Sphingobium cloacae JCM 10874T (97.3 %) and Sphingobium fuliginis MTCC 7295T (96.4 %). Phylogenetic analysis based on 16S rRNA gene sequences placed strain RL-3T between S. cloacae JCM 10874T and S. fuliginis MTCC 7295T. The DNA G+C content of strain RL-3T was 62 mol%. The DNA-DNA relatedness values of strain RL-3T with S. cloacae JCM 10874T and S. fuliginis CCM 7327T were 8.65 and 7.47 %, respectively. SGL1 was the major sphingolipid and spermidine was the major polyamine in strain RL-3T. The major fatty acids in strain RL-3T were C(18 : 1)omega7c (56.6 %), C(16 : 0) (14 %) and C(14 : 0) 2-OH (7.4 %). Ubiquinone Q-10 was the major respiratory quinone. Phylogenetic distinctiveness, DNA-DNA relatedness values, biochemical and physiological characterization and unique phenotypic characteristics suggest that strain RL-3T represents a novel species of the genus Sphingobium, for which the name Sphingobium ummariense sp. nov. is proposed. The type strain is RL-3T (=MTCC 8599T=CCM 7431T).