Reductive dechlorination of tetrachloroethene by a high rate anaerobic microbial consortium

Abstract

Tetrachloroethene (PCE) and other chloroethenes are major contaminants in groundwater, and PCE is particularly resistant to attack by aerobes. We have developed an anaerobic enrichment culture that carries out reductive dechlorination of chloroethenes to ethene at high rates, thereby detoxifying them. Although the electron donor added to the culture is methanol, our evidence indicates that H2 is the electron donor used directly for dechlorination. We have recently obtained a culture from a 10-6 dilution of the original methanol/PCE culture that uses H2 as an electron donor for PCE dechlorination. Because the culture can be transferred indefinitely and the rate of PCE dechlorination increases after inoculation, we suggest that dechlorinating organisms in the culture use the carbon-chlorine bonds in chloroethenes as electron accepters for energy conservation.