Biodiversity of Dehalorespiring Bacteria with Special Emphasis on Polychlorinated Biphenyl/Dioxin Dechlorinators

Abstract

A wide variety of haloorganic compounds undergo reductive dehalogenation by certain anaerobic microorganisms. Metabolic reductive dehalogenation is coupled with energy-conserving respiratory electron transport in which a halogenated compound is used as the terminal electron acceptor, the biological process called dehalorespiration or halorespiration. Dehalorespiring bacteria may play important roles in the geochemical cycle with organohalogens in nature and have great promise in their application to the bioremediation of haloorganic contaminants derived from anthropogenic sources. During the past decade, a number of dehalorespiring microorganisms, including a unique group of strictly dehalorespiring bacteria, "Dehalococcoides", have been isolated and characterized at phylogenetic, physiologic, and genetic levels. Also, new perspectives of dehalorespiring bacteria have emerged based on information about genomics and molecular microbial ecology. This review article focuses on up-to-date knowledge of the biodiversity of dehalorespiring bacteria and reductively dehalogenating microbial consortia with special emphasis on those capable of transforming polychlorinated biphenyls and dioxins.

Enhancing tetrabromobisphenol A biodegradation in river sediment microcosms and understanding the corresponding microbial community

“…Halogenated aromatic compounds ("haloprimers") with similar analogous structures to 1,2,3,4-tetrachlorodibenzo-p-dioxin (TeCDD)/1,2,3,4-tetrachlorodibenzofuran (TeCDF) could also effectively enhance TeCDD/F dechlorination (Ahn et al, 2005). Using halogenated cosubstrates as haloprimers could stimulate anaerobic dechlorination, because certain bacteria can use halogenated co-substrate as a terminal electron acceptor during the respiratory reductive dehalogenation or dehalorespiration process (Hiraishi, 2008). This respiratory activity may play an important role in detoxifying organohalides released into the environment (Park et al, 2011).…”

Identification and transcriptional analysis of trans-DCE-producing reductive dehalogenases in Dehalococcoides species

“…The released chloroethenes often contaminate groundwater, which in turn threatens drinking water supplies (Westrick et al, 1984). Under anaerobic conditions, PCE and TCE can be reductively dechlorinated to the less chlorinated ethenes cis-1, 2-dichloroethene (cis-DCE) and vinyl chloride (VC) by a variety of dechlorinators or to the harmless ethene by Dehalococcoides species (Holliger et al, 1998;Lö ffler et al, 2000;He et al, 2003;Luijten et al, 2003;Mü ller et al, 2004;Smidt and de Vos, 2004;He et al, 2005;Hiraishi, 2008). However, in PCE-/ TCE-contaminated sites, dechlorination often terminates at DCEs and VC.…”

Characterization of Rhizobium naphthalenivorans sp. nov. with special emphasis on aromatic compound degradation and multilocus sequence analysis of housekeeping genes

“…Microbial transformation of polychlorinated dibenzop-dioxins/dibenzofurans (PCDD/Fs) has been well documented in connection with natural attenuation and engineered bioremediation of organohalogen pollution (Field and Sierra-Alvarez, 2008;Hiraishi, 2003Hiraishi, , 2008. Previously, we constructed laboratory-scale semi-anaerobic microcosms with sediment contaminated with high concentrations of PCDD/Fs in order to study microorganisms involved in the transformation J. Gen. Appl.…”