Biodegradation of γ-hexachlorocyclohexane (lindane) by halophilic bacterium Chromohalobacter sp. LD2 isolated from HCH dumpsite

Large dumps of unused γ-hexachlorocyclohexane (γ-HCH) have become an issue of concern. The overall salinity of soil enhances due to the release of potassium cations by the insecticide in the polluted soil, which may limit microbial degradation. The current work addresses this problem through the isolation of γ-HCH degrading halophilic bacteria from HCH dumpsite using γ-HCH as a sole carbon source by selective enrichment technique. Strain LD2 was found to be the most efficient degrader, degrading 89.6% lindane in 7 days. Low amount of metabolites like 1,2,4-trichlorobenzene (1,2,4-TCB) and 2,5-dichlorophenol (2,5-DCP) were identified during the degradation. The strain was able to utilize lindane at a range of salt concentrations from 10 to 150 g L−1 NaCl where the highest degradation was achieved at 50 g L−1 of NaCl. The bacterial strain LD2 was identified as Chromohalobacter sp. LD2 on the basis of 16S rDNA sequence similarity (KU934224.1). These results revealed that Chromohalobacter sp. LD2 might be a potential candidate for bioremediation in saline environments to decontaminate γ-HCH from polluted sites.