Examining aerobic degradation of chloroethenes mixture in consortium composed of Comamonas testosteroni RF2 and Mycobacterium aurum L1

Abstract

An environmental isolate Comamonas testosteroni RF2 has been previously described to cometabolize trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), 1,2-trans-dichloroethene (tDCE), and 1,1-dichloroethene (1,1DCE) when grown on phenol and lactate sodium. In this study, three vinyl chloride (VC) degrading strains, Mycobacterium aurum L1, Pseudomonas putida PS, and Rhodococcus ruber Sm-1 were used to form consortia with the strain RF2 in terms to achieve the removal of VC along with above-mentioned chloroethenes. Degradation assays were performed for a binary mixture of cDCE and VC as well as for a mixture of TCE, all DCEs and VC. The consortium composed of C. testosteroni RF2 and M. aurum L1 showed to be the most efficient towards the removal of cDCE (6.01 mg L−1) in the binary mixture with VC (10 mg L−1) and was capable of efficiently removing chloroethenes in the mixture sample at the initial concentrations of 116 μg L−1 for TCE, 662 μg L−1 for cDCE, 42 μg L−1 for tDCE, 16 μg L−1 for 1,1DCE, and 7 mg L−1 for VC with a removal efficiency of nearly 100% for all of the compounds. Although complete removal of VC took a significantly longer time than the removal of other chloroethenes, the consortium composed of C. testosteroni RF2 and M. aurum L1 displayed strong bioremediation potential for aquifers with downstream contamination characterized by the presence of less chlorinated ethenes. © 2020 Elsevier Ltd