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...
A gram-negative, aerobic bacterium was isolated from soil; this bacterium grew in 50% (vol/vol) suspensions of 1,10-dichlorodecane (1,10-DCD) as the sole source of carbon and energy. Phenotypic and small-subunit ribosomal RNA characterizations identified the organism, designated strain 273, as a member of the genusPseudomonas. After induction with 1,10-DCD,Pseudomonas sp. strain 273 released stoichiometric amounts of chloride from C5 to C12α,ω-dichloroalkanes in the presence of oxygen. No dehalogenation occurred under anaerobic conditions. The best substrates for dehalogenation and growth were C9 to C12chloroalkanes. The isolate also grew with nonhalogenated aliphatic compounds, and decane-grown cells dechlorinated 1,10-DCD without a lag phase. In addition, cells grown on decane dechlorinated 1,10-DCD in the presence of chloramphenicol, indicating that the 1,10-DCD-dechlorinating enzyme system was also induced by decane. Other known alkane-degrading Pseudomonas species did not grow with 1,10-DCD as a carbon source. Dechlorination of 1,10-DCD was demonstrated in cell extracts of Pseudomonas sp. strain 273. Cell-free activity was strictly oxygen dependent, and NADH stimulated dechlorination, whereas EDTA had an inhibitory effect.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.