Dechlorination of Chlorocatechols by Stable Enrichment Cultures of Anaerobic Bacteria

Abstract

Metabolically stable anaerobic cultures obtained by enrichment with 5-bromovanillin, 5-chlorovanillin, catechin, and phloroglucinol were used to study dechlorination of chlorocatechols. A high degree of specificity in dechlorination was observed, and some chlorocatechols were appreciably more resistant to dechlorination than others: only 3,5-dichlorocatechol, 4,5-dichlorocatechol, 3,4,5-trichlorocatechol, and tetrachlorocatechol were dechlorinated, and not all of them were dechlorinated by the same consortium. 3,5-Dichlorocatechol produced 3-chlorocatechol, 4,5-dichlorocatechol produced 4-chlorocatechol, and 3,4,5-trichlorocatechol produced either 3,5-dichlorocatechol or 3,4-dichlorocatechol; tetrachlorocatechol produced only 3,4,6-trichlorocatechol. Incubation of uncontaminated sediments without additional carbon sources brought about dechlorination of 3,4,5-trichlorocatechol to 3,5-dichlorocatechol. 0-demethylation of chloroguaiacols was generally accomplished by enrichment cultures, except that catechin enrichment was unable to 0-demethylate tetrachloroguaiacol. None of the enrichments dechlorinated any of the polychlorinated phenols examined. The results suggested that dechlorination was not dependent on enrichment with or growth at the expense of chlorinated compounds and that it would be premature to formulate general rules for the structural dependence of the dechlorination reaction.

Degradation of Chlorinated Dibenzofurans and Dibenzo-p-Dioxins by Sphingomonas sp. Strain RW1

“…As a consequence, their further degradation demands special attention. Chlorocatechols in anaerobic environments do not pose such fundamental problems (2). These results and the turnover experiments with DF-grown resting cells ( Fig.…”

Anaerobic dechlorination of aroclor 1242 as affected by some environmental conditions

“…For the dechlorination of PCBs, acetone, acetate, methanol, or glucose enhanced the rate [20]. Supplements of yeast extract and peptone were essential for the dechlorination of 2-chlorophenol [21], and casamino acids were supplemented in a basal medium used for the dechlorination of halo-genated aromatic aldehydes and chlorocatechols by a consortium of marine sediment bacteria [22,23].…”

Microbial reductive dehalogenation.

“…The resorcinol product subsequently disappeared from enrichment cultures from the sludge, suggesting that anaerobic communities may be capable of mineralizing 4-chlororesorcinol. Chlorocatechols apparently result from the process of paper bleaching and other industrial processes and have recently been reported to be dehalogenated by enrichment cultures from marine sediments (5). Only certain chlorocatechol congeners were dehalogenated, and some variation in pathways was observed (Fig.…”

“…Subsequent studies have found similar regiospecificity for phenol dehalogenation (33,86,144). Various marine sediment enrichment cultures had distinct specificities for chlorocatechols which they dehalogenated (5). These marine sediment cultures differed in the substrates used for enrichment, which were not chlorocatechols but instead were structural analogs of chlorocatechols.…”