Microbial ecology of chlorinated solvent biodegradation

Area of Science:

• Environmental microbiology
• Bioremediation of chlorinated solvents

Background:

• Tetrachloroethene (PCE) is a widespread environmental pollutant.
• Its degradation involves complex microbial processes and toxic intermediates.

Purpose of the Study:

• To elucidate the microbial ecology of PCE degradation.
• To identify key microorganisms and functions involved in PCE breakdown to ethene.
• To understand the relationship between microbial activity and toxic metabolite accumulation.

Main Methods:

• Soil microcosms artificially contaminated with PCE.
• Addition of bromodeoxyuridine (BrdU) to label active cells.
• Phylogenetic microarrays and 454 pyrosequencing to analyze total and active bacterial communities.
• Correlation of chemical data with phylogenetic data.

Main Results:

• Identified key microbial community members and ecological functions for complete PCE degradation.
• Confirmed the crucial role of hydrogen and acetate producers for Dehalococcoides-mediated PCE degradation.
• Discovered bacteria potentially oxidizing hydrogen, indicating competition for resources.
• Demonstrated PCE degradation dependency on specific metabolite producers and hydrogen competitors.

Conclusions:

• Microbial PCE degradation is a syntrophic process requiring specific metabolic contributions.
• Community structure and function are critical for efficient remediation of PCE.
• Understanding microbial interactions is vital for optimizing bioremediation strategies.