Aerobic cometabolic degradation of cis- and trans- dichloroethene by a consortium of bacteria isolated from contaminated sites in Africa

Abstract

Biodegradation of dichloroethenes (DCEs) to innocuous products such as ethene and carbondioxide is often a limiting factor in the use of reductive dechlorination as an approach for the remediation of chloroethene-contaminated sites. In this study, the effect of some water-soluble, non-toxic and nonflammable substrates on the biodegradation of DCEs by a mixed culture of aerobic bacteria isolated from contaminated sites in Africa was investigated. A general increase of 2.13 ‐ 22.18% and 0.39 ‐ 12.61% in the amount of cis- and trans-DCE degraded, respectively, was observed in the presence of the different primary substrates. Glucose had the most significant effect resulting in 91.68% removal of cis-DCE and 86.98% removal of trans-DCE after 7 days. These values corresponded to 22.18 and 12.61% above the amount of cis- and trans-DCE degraded, respectively, in the absence of primary substrates. Results from this study indicate that the biodegradation of both compounds is enhanced by cometabolism. This finding is significant for active bioremediation systems, since the addition of these substrates to groundwater has several advantages over other cometabolic electron donors presently in use.