Thursday, July 30, 2009 - 4:00 PM
S161

Microbial Dehalogenation, Genomics and Site Remediation

Elizabeth A. Edwards, Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St, Toronto, ON M5S 3E5, Canada

Groundwater contamination is a serious threat to global health and prosperity.  Chlorinated solvents are widely used as industrial degreasers, dry-cleaning agents and precursors in chemical synthesis, and therefore are common groundwater contaminants.  Owing to their toxicity, even small spills render groundwater unsuitable for use, and cleanup is typically a costly and long-term undertaking.

Recently, a fascinating group of subsurface microorganisms, called Dehalococcoides, has been discovered that can dechlorinate the common solvents tetrachloroethene and trichloroethene to the benign product ethene.  Remarkably, these organisms obtain energy for growth from dechlorination and several successful demonstrations of bioaugmentation, where an aquifer is inoculated with culture, have lead to the development of a commercial market for dechlorinating cultures.

Community metagenome sequencing, DNA microarray expression analysis and metabolic modelling are being used to identify the important functional and regulatory elements in one such commercial culture called KB-1.  KB-1 is a strictly anaerobic, mixed microbial culture harbouring several Dehalococcoides that is very effective at detoxifying chloro-organic pollutants.  An understanding of the genetic and physiological diversity in the culture, as well as interspecies interactions is sought to identify key biomarkers to improve the success of bioremediation.