16S rRNA Gene-Based Detection of Tetrachloroethene-DechlorinatingDesulfuromonasandDehalococcoidesSpecies

Abstract

Members of the genera Desulfuromonas and Dehalococcoides reductively dechlorinate tetrachloroethene (PCE) and trichloroethene. Two primer pairs specific to hypervariable regions of the 16S rRNA genes of the Dehalococcoides group (comprising Dehalococcoides ethenogenes and Dehalococcoides sp. strain FL2) and the acetate-oxidizing, PCE-dechlorinating Desulfuromonas group (comprising Desulfuromonas sp. strain BB1 and Desulfuromonas chloroethenica) were designed. The detection threshold of a nested PCR approach using universal bacterial primers followed by a second PCR with the Desulfuromonas dechlorinator-targeted primer pair was 1 ؋ 10 3 BB1 cells added per gram (wet weight) of sandy aquifer material. Total community DNA isolated from sediments of three Michigan rivers and six different chloroethene-contaminated aquifer samples was used as template in nested PCR. All river sediment samples yielded positive signals with the BB1-and the Dehalococcoides-targeted primers. One chloroethene-contaminated aquifer tested positive with the Dehalococcoides-targeted primers, and another contaminated aquifer tested positive with the Desulfuromonas dechlorinator-targeted primer pair. Restriction fragment analysis of the amplicons could discriminate strain BB1 from other known Desulfuromonas species. Microcosm studies confirmed the presence of PCE-dechlorinating, acetate-oxidizing Desulfuromonas and hydrogenotrophic Dehalococcoides species in samples yielding positive PCR signals with the specific primers.Tetrachloroethene (PCE) and trichloroethene (TCE) are abundant groundwater pollutants (1). PCE and TCE can be transformed to less chlorinated ethenes in anaerobic cometabolic processes mediated by methanogenic, homoacetogenic, and sulfate-reducing microorganisms (6, 13). Other groups of bacteria, like Desulfuromonas sp. strain BB1 and Desulfuromonas chloroethenica, Dehalospirillum multivorans, Dehalobacter restrictus strains PER-K23A and TEA, Enterobacter sp. strain MS1, Dehalococcoides ethenogenes, and Desulfitobacterium sp. strain PCE-S (summarized in reference 8), can reduce PCE and TCE in terminal electron accepting processes (chlororespiration). Reductive dechlorination of PCE and TCE in respiratory processes is orders of magnitude faster than anaerobic cometabolic reduction. Hence, the stimulation of respiratory organochlorine reducing bacteria (OCRB) is a promising and cost-effective approach for the remediation of PCE-contaminated sites.The only available pure culture to date that is capable of complete reductive dechlorination of PCE to ethene is the obligately hydrogenotrophic organism D. ethenogenes (16,17). Hydrogen is generally considered the ultimate electron donor to stimulate the reductive dechlorination of chloroethenes. Desulfuromonas sp. strain BB1 and D. chloroethenica are unique dechlorinators in regard to their electron donor requirements: acetate, but not hydrogen, supports the reductive dechlorination of PCE and TCE (9; F. E. Löffler, J. Li, J. W. Urbance, and J. M. Tiedje, Abstr. 98th Gen. Meet. Am. Soc...

Dechlorination and organohalide-respiring bacteria dynamics in sediment samples of the Yangtze Three Gorges Reservoir

“…4b). These cultures showed complete dechlorination, thus confirming previous reports that bacteria of the Dehalococcoides group are the only known microorganism to completely dehalogenate PCE to ethene (Holliger et al 1999;Löffler et al 2000;Maymó-Gatell et al 2001;Hendrickson et al 2002;Smidt and de Vos 2004;Schmidt et al 2006). During 28 weeks and anaerobic transformation of approximately 60 mg/L PCE, the Dehalococcoides spp.…”

“…Although in both cultures, YCQ1 and XX07, complete dechlorination to ethene was observed, the temporarily detected metabolites differed. As in most previous studies (Löffler et al 2000;Schmidt and Tiehm 2008;Aktaş et al 2012), dechlorination via cis-DCE without any detection of trans-DCE was observed in culture YCQ1 (Fig. 3a).…”

“…There are several groups of bacteria which are able to dehalogenate chlorinated aliphatic and aromatic hydrocarbons under anaerobic conditions. Remarkably, similar groups of bacteria have been reported to be capable of dechlorination of CBs (Field and Sierra-Alvarez 2008;Taş et al 2011), PCBs (Bedard 2008), and chlorinated ethenes (Löffler et al 2000;Schmidt et al 2006). In this study, chloroethenes were used as model compounds.…”

“…(Lohner and Tiehm 2009), Desulfitobacterium dehalogenans and Desulfomonile tiedjei (El Fantroussi et al 1997), Desulfuromonas spp. and Dehalococcoides mccartyi (Löffler et al 2000;Löffler et al 2012), Dehalobacter spp. and Dehalococcoides spp.…”

“…It has been shown recently that in the field, often several dechlorinating bacteria are present simultaneously (Rouzeau-Szynalski et al 2011). In the environment, the reductively dechlorinating bacteria have been detected in different compartments, mainly in contaminated soil (Löffler et al 2000;Hendrickson et al 2002) and polluted groundwater (Schmidt et al 2006;Schmidt and Tiehm 2008;Vancheeswaran et al 1999). For river sediments, their occurrence in the Dutch part of the Rhine River (Holliger et al 1993), the Red Cedar, Père Marquette (Löffler et al 2000), Tahquamenon and Pine Rivers in the USA, and the Perfume River in Vietnam (Griffin et al 2004) was reported.…”