Inhibition of aerobic metabolic cis-1,2-di-chloroethene biodegradation by other chloroethenes

The presence of other chloroethenes influences aerobic metabolic biodegradation of cis-1,2-dichloroethene (cDCE). A new metabolically cDCE degrading enrichment culture was identified as also being capable of degrading vinyl chloride (VC), but not 1,1-dichloroethene (1,1DCE), trans-1,2-dichloroethene (tDCE), trichloroethene (TCE), or tetrachloroethene (PCE). The fastest degradation of cDCE was observed in the absence of any other chloroethene. In the presence of a second chloroethene (40-90 μM), the rate of cDCE (60 μM) degradation decreased in the following order: cDCE (+PCE) > cDCE (+tDCE) > cDCE (+VC)> cDCE (+1,1DCE) ≈ cDCE (+TCE). With increasing concentrations of VC, ranging from 10 to 110 μM, the rate of cDCE (60 μM) degradation decreased. This study demonstrates that the inhibiting effects of chloroethene mixtures have to be considered during laboratory studies and bioremediation approaches based on metabolic cDCE degradation.