Isolation and characterization of a novel Gram-negative bacterium Chromobacterium alkanivorans sp. nov., strain IITR-71T degrading halogenated alkanes.

Abstract

The taxonomic position of a Gram-stain negative, non-violaceinpigmented bacterium isolated from an insecticide-contaminated site was characterized by a polyphasic approach. The bacterium was able to grow on three different halogenated compounds namely 1-hlorobutane, 1-hloropropane and 1,2-ichloroethane. As a critical step in the degradation of these haloalkanes, stoichiometric amounts of dechlorination were estimated. Based on selective enrichment method for three months, using a highly contaminated mixed chemical soil, a bacterium was obtained and designated as IITR-71T. Its versatility and novelty led us to further characterize it by polyphasic taxonomy. The 16S rRNA gene sequence (1446 bases) comparison showed highest similarity with those of members of the genus Chromobacterium with the most closely related species to strain IITR-71T being Chromobacterium aquaticum (99.3 %) followed by Chromobacterium haemolyticum (98.6 %) and Chromobacterium piscinae (97.1 %). The major ubiquinone was Q-8. Predominant polar lipids are phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG). The DNA G+C content of IITR-71T was estimated to be 61.2 mol%. The genotypic and phenotypic distinctiveness of IITR-71T and its phylogenetic relationships indicate that IITR-71T represents a novel species, for which the name Chromobacterium alkanivorans sp. nov. is proposed. The type strain is IITR-71T (=MTCC 11059T=JCM 30068T=KCTC 52433T).