1,2-DCA and VC degradation by VC-enriched and 1,2-DCA-enriched anaerobic cultures

Abstract

An anaerobic mixed microbial culture which degraded trichloroethylene to ethene was enriched on 1,2-dichoroethane (1,2-DCA). This enrichment and KB1-VC/H2, an anaerobic mixed microbial culture which was capable of sustained vinyl chloride (VC) degradation, were inocula for inhibition experiments where the interactions between 1,2-DCA, VC and chloroform (CF) were investigated. The 1,2-DCA culture degraded 1,2-DCA first within 10 days and eventually degraded VC after a sixty-day lag. The VC culture could degrade VC and 1,2-DCA simultaneously within ten to forty days. In the 1,2-DCA culture, 1,2-DCA was likely degraded by an organism suspected to be Syntrophus-KB1. In the VC culture, 1,2-DCA was degraded by Dehalococcoides-KB1 or by the unidentified organism. VC was a competitive inhibitor of 1,2-DCA degradation with an inhibition constant of 55muM. CF was a non-competitive inhibitor of 1,2-DCA and VC degradations: inhibition constants were equal to 10muM for 1,2-DCA degradation and 1.6muM for VC degradation.