Tetrachloroethene, also known as perchloroethylene (PCE), is a common groundwater contaminant throughout the United States. The incomplete reductive dechlorination of PCE--resulting in accumulations of trichloroethene, dichloroethene isomers, and/or vinyl chloride--has been observed by many investigators in a wide variety of methanogenic environments. Previous mixed-culture studies have demonst...

1,1,2-trichloroethane (1,1,2-TCA) has become a common groundwater pollutant due to historically extensive utilization, improper disposal, as well as from incomplete dechlorination of 1,1,2,2-tetrachloroethane. Currently, limited information is available on microbial detoxification of 1,1,2-TCA. Desulfitobacterium sp. strain PR, which was isolated from an anaerobic bioreactor maintained to dechl...

Oxygen-sensitive Dehalococcoides bacteria play crucial roles in detoxification of chlorinated contaminants (e.g., chlorinated ethenes), and bioremediation monitoring relies on quantification of Dehalococcoides DNA and RNA biomarkers. To explore the effects of oxygen on Dehalococcoides activity, viability, and biomarker quantification, batch experiments with a tetrachloroethene-to-ethene dechlor...

Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlori...

This genome report describes the draft genome and the physiological characteristics of Desulfitobacterium hafniense PCE-S, a Gram-positive bacterium known to dechlorinate tetrachloroethene (PCE) to dichloroethene by a PCE reductive dehalogenase. The draft genome has a size of 5,666,696 bp with a G + C content of 47.3%. The genome is very similar to the already sequenced Desulfitobacterium hafni...

In chloroethene-contaminated sites undergoing in situ bioremediation, groundwater acidification is a frequent problem in the source zone, and buffering strategies have to be implemented to maintain the pH in the neutral range. An alternative to conventional soluble buffers is silicate mineral particles as a long-term source of alkalinity. In previous studies, the buffering potentials of these m...

Chloroethenes like tetrachloroethene (PCE) are the most prevalent groundwater contaminants in the USA. Their presence as nonaqueous phase liquids (NAPLs) makes remediation difficult. Among options for NAPL cleanup, co-solvent injection has demonstrated success. However, the process has the potential to leave considerable residue of the co-solvent as well as residual chloroethene. Our rationale ...

In this study, nanoscale zero-valent iron (NZVI) particles were synthesized and used for the reductive dehalogenation of short chain chlorinated paraffins (SCCPs) in the laboratory. The results show that the dechlorination rate of chlorinated n-decane (CP(10)) by NZVI increased with decreased solution pH. Increasing the loading of NZVI enhanced the dechlorination rate of CP(10). With an increas...

Microbial reductive dechlorination of commercial polychlorinated biphenyl (PCB) mixtures (e.g., Aroclors) in aquatic sediments is crucial to achieve detoxification. Despite extensive efforts over nearly two decades, the microorganisms responsible for Aroclor dechlorination remained elusive. Here we demonstrate that anaerobic bacteria of the Dehalococcoides group derived from sediment of the Hou...

Under secondary metabolic conditions, the lignin-degrading basidiomycete Phanerochaete chrysosporium mineralizes 2,4, 6-trichlorophenol. The pathway for the degradation of 2,4, 6-trichlorophenol has been elucidated by the characterization of fungal metabolites and oxidation products generated by purified lignin peroxidase (LiP) and manganese peroxidase (MnP). The multistep pathway is initiated ...