Dehalogenation of lindane (γ-hexachlorocyclohexane) by anaerobic bacteria from marine sediments and by sulfate-reducing bacteria

Abstract

Marine sediments from around burrows of Saccoglossus kowalevskii, a tribromopyrrole-producing marine hemichordate, were used to develop anaerobic enrichment cultures supplemented with lindane and a mixture of short chain fatty acids. These enrichments consumed lindane and both monochlorobenzene and benzene were detected as transformation products. Cultures transferred to sediment-free media containing citrate, lactate, yeast extract and sulfate also dehalogenated lindane. Lindane transformation was inhibited by the addition of molybdate. Lindane loss was not observed when the enrichment was cultured on lactate and citrate in the absence of sulfate, suggesting that sulfate-reducing bacteria transform lindane. Monochlorobenzene and benzene were identified as two transformation products in the lactate, citrate and sulfate enrichment culture. Pure cultures were used in order to confirm the ability of sulfate-reducing bacteria to dehalogenate lindane. Cell suspensions of Desulfovibrio gigas ATCC 19364, Desulfovibrio africanus ATCC 19997 and Desulfococcus multivorans ATCC 33890 were also able to dehalogenate lindane to benzene and monochlorobenzene. Actively growing and autoclaved cell suspensions of Desulfovibrio gigas were capable of lindane transformation while filter-sterilized cultures were not.