Bioaugmentation with distinct Dehalobacter strains achieves chloroform detoxification in microcosms

Area of Science:

• Environmental microbiology
• Bioremediation
• Groundwater remediation

Background:

• Chloroform (CF) is a persistent groundwater contaminant resistant to aerobic breakdown.
• Anoxic degradation of CF is often incomplete, failing to achieve full detoxification.
• Novel Dehalobacter strains capable of CF and DCM metabolism offer bioremediation potential.

Purpose of the Study:

• To assess the feasibility of anaerobic bioremediation for CF and DCM using specific Dehalobacter strains.
• To develop and validate qPCR assays for tracking these Dehalobacter populations.
• To evaluate bioaugmentation and biostimulation strategies in laboratory microcosms.

Main Methods:

• Development of 16S rRNA gene-based qPCR assays for specific Dehalobacter strains.
• Laboratory treatability study using anoxic microcosms with contaminated aquifer material.
• Application of bioaugmentation with CF-degrading and DCM-degrading Dehalobacter cultures.
• Investigation of biostimulation using bicarbonate.

Main Results:

• Bioaugmentation with Dhb-CF culture successfully dechlorinated CF to DCM.
• Subsequent augmentation with RM consortium achieved complete DCM degradation with bicarbonate addition.
• Simultaneous inoculation also led to CF and DCM degradation and population growth.
• CT significantly inhibited both CF and DCM degradation processes.

Conclusions:

• Anaerobic bioremediation, particularly bioaugmentation with specific Dehalobacter strains, is a viable strategy for CF and DCM contaminated sites.
• The developed qPCR assays are effective for monitoring Dehalobacter populations during remediation.
• The absence of CT is crucial for successful organohalide respiration and fermentation.