Alpha-, Beta-, Delta-, and Gamma- hexachlorocyclohexane dechlorinating enrichment cultures

Intensive historical and worldwide use of the persistent pesticide technical-grade hexachlorocyclohexane (HCH), composed of the active ingredient ?-HCH (called lindane) along with several other HCH isomers, has led to widespread contamination. We derived four anaerobic enrichment cultures from HCH-contaminated soil capable of sustainably dechlorinating each of a-, ß-, ?-, and d-HCH isomers stoichiometrically and completely to benzene and monochlorobenzene (MCB) over two years. Cultivation with a different HCH isomer resulted in distinct bacterial communities. This study provides the first direct comparison of shifts in anaerobic microbial communities induced by the dechlorination of distinct HCH isomers.