Research Article: Efficient Biodegradation of Lindane (γ-HCH) by Indigenous Bacteria Isolated from the Ganga River, Prayagraj, India

Lindane (γ-HCH) is a persistent organochlorine insecticide extensively used in agriculture and is recognized as a major source of environmental contamination in aquatic ecosystems. The present study aimed to isolate and characterize indigenous bacterial strains capable of degrading lindane from contaminated water of the Ganga River at Prayagraj, India. Bacterial isolates were obtained using enrichment culture and spray-plate techniques, resulting in ten distinct isolates, among which one strain (ASNY6) showed significant lindane-degrading capability. Preliminary identification was carried out through morphological observations and biochemical characterization. The degradation potential of HCH isomers was further evaluated using a colorimetric assay based on pH variation. The selected isolate demonstrated efficient growth in mineral medium containing 100 ppm lindane as the sole carbon source under optimal conditions of pH 7 and 30°C. Degradation of lindane was further confirmed by thin-layer chromatography (TLC) and gas chromatography–mass spectrometry (GC–MS) analyses. GC–MS results revealed the formation of pentachlorocyclohexane (PCCH) as an intermediate metabolite during the biodegradation process. These findings highlight the capability of indigenous bacterial strains to transform lindane and suggest their potential application in the bioremediation of lindane-contaminated aquatic environments.