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AIM The goal of this study was to compare the degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by three Rhodococcus strains under anaerobic, microaerophilic (<0.04 mg l(-1) dissolved oxygen) and aerobic (dissolved oxygen (DO) maintained at 8 mg l(-1)) conditions. METHODS AND RESULTS Three Rhodococcus strains were incubated with no, low and(More)
A systematic evaluation of the ability of different bacterial genera to transform 2,4,6-trinitrotoluene (TNT), and grow in its presence, was conducted. Aerobic Gram-negative organisms degraded TNT and evidenced net consumption of reduced metabolites when cultured in molasses medium. Some Gram-negative isolates transformed all the initial TNT to undetectable(More)
We employed stable isotope probing (SIP) with (13)C-labeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to identify active microorganisms responsible for RDX biodegradation in groundwater microcosms. Sixteen different 16S rRNA gene sequences were derived from microcosms receiving (13)C-labeled RDX, suggesting the presence of microorganisms able to(More)
This study reported the application of 15N-stable isotope probing (SIP) to identify active hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-utilizing microorganisms in groundwater microcosms. Fifteen 16S rRNA gene sequences were derived from the 15N-DNA fraction (contributed from active microorganisms capable of using RDX as a nitrogen source) of microcosms(More)
Hexahydro-1,3,5-trinitro-1,3,5,-triazine (RDX) is a toxic and mobile groundwater contaminant common to military sites. This study compared in situ RDX degradation rates following bioaugmentation with Gordonia sp. strain KTR9 (henceforth KTR9) to rates under biostimulation conditions in an RDX-contaminated aquifer in Umatilla, OR. Bioaugmentation was(More)
Bacterial transport experiments were conducted using intact sediment cores collected from sites on the Delmarva Peninsula near South Oyster, VA, to delineate the relative importance of physical and chemical heterogeneity in controlling transport of an adhesion-deficient bacterial strain. Electron microscopy revealed that the sediments consisted of quartz(More)
Changes in the microbial community during bioremediation of explosives-contaminated soil in a molasses-fed bioslurry process were examined. Upon addition of molasses to laboratory-scale reactors, total culturable heterotrophs increased rapidly by three to four orders of magnitude. However, heat-shocked heterotrophs and the percentage of gram-positive(More)
Laboratory and field-scale studies with stained cells were performed to monitor cell growth in groundwater systems. During cell division, the fluorescence intensity of the protein stain 5-(and 6-)-carboxyfluorescein diacetate succinimidyl ester (CFDA/SE) for each cell is halved, and the intensity can be tracked with a flow cytometer. Two strains of(More)
We report the ability of nickel-based catalysts to degrade explosives compounds in aqueous solution. Several nickel catalysts completely degraded the explosives, although rates varied. Nearly all of the organic explosive compounds tested, including 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and(More)
The transformation of explosives, including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), by xenobiotic reductases XenA and XenB (and the bacterial strains harboring these enzymes) under both aerobic and anaerobic conditions was assessed. Under anaerobic conditions, Pseudomonas fluorescens I-C (XenB) degraded RDX faster than Pseudomonas putida II-B (XenA),(More)