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

Abstract

The ability of the dibenzofuran-and dibenzo-p-dioxin-mineralizing bacterium Sphingomonas sp. strain RW1 (R.-M. Wittich, H. Wilkes, V. Sinnwell, W. Francke, and P. Fortnagel, Appl. Environ. Microbiol. 58:1005-1010, 1992) to oxidize chlorinated derivatives of dibenzofuran and dibenzo-p-dioxin was analyzed. Strain RW1 degraded several mono-and dichlorinated dibenzofurans and dibenzo-p-dioxins, but it did not degrade more highly chlorinated congeners. Most mono-and dichlorinated dibenzofurans and dibenzo-p-dioxins investigated in this study were degraded to the corresponding mono-and dichlorinated salicylates and catechols, respectively, together with salicylate and catechol. This indicates an initial dioxygenolytic attack on the substituted as well as on the nonsubstituted aromatic nucleus of most of the target compounds. Strain RW1 could not grow at the expense of monochlorinated dibenzo-p-dioxins and dibenzofurans as carbon sources, with the exception of 4-chlorodibenzofuran, which was stoichiometrically converted to 3-chlorosalicylate.

Isolation and characterization of dibenzofuran-degrading bacteria

“…Dioxin-degrading bacteria discovered so far do not show a full dioxin-degrading ability in the presence of other carbon sources or other bacteria in nature. It appears that the intermediates of PCDDs and PCDFs, such as chlorocatechols, inhibit enzymes catalyzing the degradation reaction [16]. Therefore, it is essential to elucidate the mechanism of regulation and substrate recognition of dioxin-degrading enzymes.…”

Occurrence of an α-galacturonosyl-ceramide in the dioxin-degrading bacterium Sphingomonas wittichii

“…In our recent study of dioxin-degrading bacteria, Sphingomonas wittichii was found to have a GSL pro¢le identical to that of S. yanoikuyae. S. wittichii was isolated from the water of the Elbe River as a dioxin degrader [10] and its dioxin metabolism [11,12] as well as taxonomic position [13] have been studied intensively. The membrane permeability of such substances is an important factor in the ability to degrade dioxins and other hydrophobic substances, and it may correlate with the pro¢le and the structure of membrane lipids, especially those of GSL.…”

Development of a highly sensitive assay for enzyme‐mediated reductive degradation of polychlorinated dibenzo‐p‐dioxin

“…In recent years, attention has been directed toward developing technology to clean up these environmental pollutants by bioremediation [3][4][5][6][7][8][9][10][11][12]. Rapid advances have also been made in the analysis of dioxins in the field of environmental biotechnology.…”