Characterization and Applications of Reductive Dehalogenase Genes in Enhancement and Monitoring of Biodegradation of Chlorinated Pollutants

EPA Grant Number: R830250
Title: Characterization and Applications of Reductive Dehalogenase Genes in Enhancement and Monitoring of Biodegradation of Chlorinated Pollutants
Investigators: Tiedje, James M. , Davis, John M.G. , Hashsham, Syed
Institution: Michigan State University
EPA Project Officer: Lasat, Mitch
Project Period: September 1, 2002 through August 31, 2004
Project Amount: $249,842
RFA: Futures Research in Natural Sciences (2001) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Land and Waste Management , Hazardous Waste/Remediation


Of the currently known reductive dehalogenase genes, few have functions assigned, and it seems likely that many more remain to be discovered. Very little is known of the ecology of the organisms that harbor these genes, that encode enzymes that are key to the anaerobic dechlorination and detoxification of chlorinated pollutants. The construction of a microarray including all known reductive dehalogenase genes would allow for the detection of these genes at contaminated sites. Sites with reductive dechlorination activity that do not hybridize to the known genes would potentially yield new genes of this family. Use of the microarray to detect messenger RNA molecules transcribed in response to exposure of pure cultures to various chlorinated compounds would aid I the assignmnet of function to those of unknown function. The assignmnet of function, discovery of new functions, and understanding of the ecology of these organisms would aid in the removal of these pollutants from the environment


We currently possess the full length sequences of at least 21 reductive dehalogenas-like genes, and partial sequences for many more. We will ontain the full sequences of as many of these genes as we can discover. The sequences will be used to build a microarray. DNA and RNA will be extracted from soil and sediment samples at contaminated and pristine sites and pure cultures and hybridized to the array.

Expected Results:

It is expected that the microarray will allow for the detection of reductive dehalogenase genes at contaminated sites. In addition, the activity of the genes can be monitored indirectly by determining the level of transcription of the genes. This will allow for an assessment of the potential for the removal of chlorinated compounds from the site. If the genes are absent or the activity is low, it would indicate that it may be necessary to alter the site by addition of nutrients or dechlorinating organisms. Additional benefits may be the discovery of novel reductive dehalogenase genes, understanding of the functions and regulation of the genes, and knowledge of the distribution and ecology of reductively dehalogenating microbes.

Publications and Presentations:

Publications have been submitted on this project: View all 7 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 3 journal articles for this project

Supplemental Keywords:

Desulfitobacterium, Dehalospirillum, Dehalobacter, Dehalococcoides, Desulfomonile, Desulfovibrio, Perchloroethylene, Trichloroethylene, Chlorophenol, Chlorobenzoate, RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Restoration, Environmental Monitoring, Ecology and Ecosystems, Aquatic Ecosystem Restoration, Futures, Exp. Research/future, dechlorination, biodiversity, conservation, contaminant uptake, ecological pollutants, exploratory research, reductive dehalogenase genes, environmental rehabilitation, environmental stress

Progress and Final Reports:

  • 2003
  • Final Report