Microbial dechlorination of historically present and freshly spiked chlorinated dioxins and diversity of dioxin-dechlorinating populations

作者：Andrei L. Barkovskii, Peter Adriaens · 发表于：Applied and Environmental Microbiology · 年份：1996 · DOI：10.1128/aem.62.12.4556-4562.1996 · 被引用次数：123 · 研究领域：Microbial bioremediation and biosurfactants、Toxic Organic Pollutants Impact、Environmental remediation with nanomaterials

The ability of a microbial consortium eluted from dioxin-contaminated Passaic River sediments to dechlorinate polychlorinated dibenzo-p-dioxins (PCDDs) was investigated under methanogenic conditions. Aged 2,3,7,8-tetraCDD, which had partitioned into the microbial consortium from sediments, was stoichiometrically converted to tri- and monoCDD congeners. During dechlorination, dominant microbial activity within the consortium shifted from methanogenic to nonmethanogenic activity. Freshly spiked octaCDD was converted to hepta-, hexa-, penta-, tetra-, tri-, di-, and monochlorinated isomers, but the reaction stoichiometry was not determined. No methanogenic activity was observed, and the maximum yield of protein coincided with the production of less-chlorinated DD congeners. Two distinct pathways of dechlorination were observed: the peri-dechlorination pathway of 2,3,7,8-substituted hepta- to pentaCDDs, resulting in the production of 2,3,7,8-tetraCDD, and the peri-lateral dechlorination pathway of non-2,3,7,8-substituted congeners. Direct evidence of further lateral dechlorination of 2,3,7,8-tetraCDD was obtained from the historically contaminated incubations; no isomer-specific identification of triCDDs in spiked incubations was determined. Pasteurized cells exhibited no peri-dechlorination pathway, and triCDDs were the least-chlorinated congeners produced in these treatments. These results demonstrate that (i) both freshly spiked and aged PCDDs are available to microbial reducti...