Assessment of reductive dechlorination of vinyl chloride and characterization of enrichments that grow on vinyl chloride as the sole carbon and energy source

Dehalogenation of vinyl bromide (VB) was investigated as a surrogate measurement for the dechlorination potential of vinyl chloride (VC). A substantially shorter (up to 5–7 times) incubation time would be required to detect the same level of reductive dehalogenation activity using VB as a surrogate for VC in treatability assessments.; Molecular methods were used to compare the microbial communities of these two enrichments those were able to reduce trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE) to ethene. The results led to the identification of an organism closely related to Dehalococcoides ethenogenes as the presumptive dechlorinator in both enrichments. Different electron acceptors affected the bacterial diversity and the community profiles of the two enrichments. Most of the sequences identified shared high similarities with sequences previously obtained from other dechlorinating cultures and contaminated aquifers.; A stable anaerobic enrichment was established at room temperature (20–22°C) in which vinyl chloride served as the sole carbon and energy source in mineral media following repeated transfers and dilutions for over 3 years. Stoichiometric chloride production confirmed the dechlorination of VC. CO₂ accounted for >60% of the product from degradation of 13C-VC. Members within the Cytophaga-Flexibacter-Bacteroides (CFB) group were found to be predominant in the clone libraries of the enrichment.; An aerobic VC-oxidizing consortium has been established that can grow on VC as sole carbon and energy source at 22°C in mineral media following repeated transfers for over 2 years. The enrichment was able to transform VB (vinyl bromide), cis-DCE (cis-dichloroethene) and TCE (trichloroethane) but not 1,1,1-TCA (1,1,1-trichloroethane). A Flexibacter sp. was found to be the most abundant in the clone library and its 16s rDNA sequence was nearly identical to the dominant sequence identified in the seeded anaerobic VC-enrichment.; An ethene enrichment was developed using seed from an anaerobic VC-degrading culture. It was able to aerobically degrade VC and other halogenated compounds such as VB and cis-DCE but not TCE. Under anaerobic condition, the culture was still able to degrade VC, but the transformation rate was much slower than that under aerobic condition. Novel Flexibacter species were found to be the most abundant in the ethene-enriched culture.