Metagenome-Guided Proteomic Quantification of Reductive Dehalogenases in the -Containing Consortium SDC-9.

At groundwater sites contaminated with chlorinated ethenes, fermentable substrates are often added to promote reductive dehalogenation by indigenous or augmented microorganisms. Contemporary bioremediation performance monitoring relies on nucleic acid biomarkers of key organohalide-respiring bacteria, such as (). Metagenome sequencing of the commercial, -containing consortium, SDC-9, identified 12 reductive dehalogenase (RDase) genes, including (two copies), , and , and allowed for specific detection and quantification of RDase peptides using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS).

Carbon Isotope Fractionation of 1,2-Dibromoethane by Biological and Abiotic Processes.

1,2-Dibromethane (EDB) is a toxic fuel additive that likely occurs at many sites where leaded fuels have impacted groundwater. This study quantified carbon (C) isotope fractionation of EDB associated with anaerobic and aerobic biodegradation, abiotic degradation by iron sulfides, and abiotic hydrolysis. These processes likely contribute to EDB degradation in source zones (biodegradation) and in more dilute plumes (hydrolysis).

Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures.

Unlabelled: Kinetic isotopic fractionation of carbon and nitrogen during RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation was investigated with pure bacterial cultures under aerobic and anaerobic conditions. Relatively large bulk enrichments in (15)N were observed during biodegradation of RDX via anaerobic ring cleavage (ε(15)N = -12.7‰ ± 0.

Evaluation of microbial transport during aerobic bioaugmentation of an RDX-contaminated aquifer.

In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient bacterial transport tests of site groundwater containing chloride or bromide tracer and either a mixed culture of Gordonia sp. KTR9 (xplA (+)Km(R)), Rhodococcus jostii RHA1 (pGKT2 transconjugant; xplA (+)Km(R)) and Pseudomonas fluorescens I-C (xenB (+)), or a single culture of Gordonia sp.

Laboratory evaluation of bioaugmentation for aerobic treatment of RDX in groundwater.

The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the transport and RDX degradation capacity of the known RDX degrading bacterial strains Gordonia sp. KTR9 (modified with a kanamycin resistance gene) Pseudomonas fluorescens I-C, and a kanamycin resistant transconjugate Rhodococcus jostii RHA1 pGKT2:Km+.

Detection of Dehalococcoides spp. by peptide nucleic acid fluorescent in situ hybridization.

Chlorinated solvents including tetrachloroethene (perchloroethene and trichloroethene), are widely used industrial solvents. Improper use and disposal of these chemicals has led to a widespread contamination. Anaerobic treatment technologies that utilize Dehalococcoides spp.

Bioaugmentation for treatment of dense non-aqueous phase liquid in fractured sandstone blocks.

Laboratory experiments were performed in discretely fractured sandstone blocks to evaluate the use of bioaugmentation to treat residual dense non-aqueous phase liquid (DNAPL) tetrachloroethene (PCE). Significant dechlorination of PCE and growth of Dehalococcoides spp. (DHC) occurred within the fractures.

Large-scale production of bacterial consortia for remediation of chlorinated solvent-contaminated groundwater.

Chlorinated solvents such as perchloroethylene (PCE) and trichloroethylene (TCE) continue to be significant groundwater contaminants throughout the USA. In many cases efficient bioremediation of aquifers contaminated with these chemicals requires the addition of exogenous microorganisms, specifically members of the genus Dehalococcoides (DHC). This process is referred to as bioaugmentation.

Bioaugmentation for chlorinated ethenes using Dehalococcoides sp.: comparison between batch and column experiments.

Batch and column experiments were performed to evaluate the transport, growth and dechlorination activity of Dehalococcoides sp. (DHC) during bioaugmentation for chlorinated ethenes. Batch experiments showed that the reductive dechlorination of trichloroethene (TCE), cis-1,2-dichloroethene (DCE), and vinyl chloride (VC), as well as growth of the DHC, were well described by the Monod kinetic model.

Biodegradation of bis(2-chloroethyl) ether by Xanthobacter sp. strain ENV481.

Degradation of bis(2-chloroethyl) ether (BCEE) was observed to occur in two bacterial strains. Strain ENV481, a Xanthobacter sp. strain, was isolated by enrichment culturing of samples from a Superfund site located in the northeastern United States.

Biodegradation of ether pollutants by Pseudonocardia sp. strain ENV478.

A bacterium designated Pseudonocardia sp. strain ENV478 was isolated by enrichment culturing on tetrahydrofuran (THF) and was screened to determine its ability to degrade a range of ether pollutants. After growth on THF, strain ENV478 degraded THF (63 mg/h/g total suspended solids [TSS]), 1,4-dioxane (21 mg/h/g TSS), 1,3-dioxolane (19 mg/h/g TSS), bis-2-chloroethylether (BCEE) (12 mg/h/g TSS), and methyl tert-butyl ether (MTBE) (9.

Application of a vital fluorescent staining method for simultaneous, near-real-time concentration monitoring of two bacterial strains in an Atlantic coastal plain aquifer in Oyster, Virginia.

Two differentially labeled bacterial strains were monitored in near-real time during two field-scale bacterial transport experiments in a shallow aquifer in July 2000 and July 2001. Comamonas sp. strain DA001 and Acidovorax sp.

Enhancing transport of hydrogenophaga flava ENV735 for bioaugmentation of aquifers contaminated with methyl tert-butyl ether.

The gasoline oxygenate methyl tert-butyl ether (MTBE) has become a widespread contaminant in groundwater throughout the United States. Bioaugmentation of aquifers with MTBE-degrading cultures may be necessary to enhance degradation of the oxygenate in some locations. However, poor cell transport has sometimes limited bioaugmentation efforts in the past.