Biodegradation Kinetics of 1,4-Dioxane in Chlorinated Solvent Mixtures

Abstract

This study investigated the impacts of individual chlorinated solvents and their mixtures on aerobic 1,4-dioxane biodegradation by Pseudonocardia dioxanivorans CB1190. The established association of these co-occurring compounds suggests important considerations for their respective biodegradation processes. Our kinetics and mechanistic studies demonstrated that individual solvents inhibited biodegradation of 1,4-dioxane in the following order: 1,1-dichloroethene (1,1-DCE) > cis-1,2-diochloroethene (cDCE) > trichloroethene (TCE) > 1,1,1-trichloroethane (TCA). The presence of 5 mg L(-1) 1,1-DCE completely inhibited 1,4-dioxane biodegradation. Subsequently, we determined that 1,1-DCE was the strongest inhibitor of 1,4-dioxane biodegradation by bacterial pure cultures exposed to chlorinated solvent mixtures as well as in environmental samples collected from a site contaminated with chlorinated solvents and 1,4-dioxane. Inhibition of 1,4-dioxane biodegradation rates by chlorinated solvents was attributed to delayed ATP production and down-regulation of both 1,4-dioxane monooxygenase (dxmB) and aldehyde dehydrogenase (aldH) genes. Moreover, increasing concentrations of 1,1-DCE and cis-1,2-DCE to 50 mg L(-1) respectively increased 5.0-fold and 3.5-fold the expression of the uspA gene encoding a universal stress protein. In situ natural attenuation or enhanced biodegradation of 1,4-dioxane is being considered for contaminated groundwater and industrial wastewater, so these results will have implications for selecting 1,4-dioxane bioremediation strategies at sites where chlorinated solvents are present as co-contaminants.

Remediating 1,4-dioxane-contaminated water with slow-release persulfate and zerovalent iron

“…Examples of techniques that have successfully removed 1,4-dioxane from contaminated groundwater include biodegradation (Zhang et al, 2016; Steffan, 2007) and chemical oxidation (Schreier et al, 2006; Vescovi et al, 2010). Advanced oxidative processes (AOPs) have been implemented at multiple sites to treat extracted groundwater containing 1,4-dioxane.…”

1,4‐Dioxane‐contaminated groundwater remediation in the anode chamber of a microbial fuel cell

“…The maximum power densities obtained in this study were comparable to the reported values in the literature for treatment of phenanthrene and benzene, as well as benzene‐ and ammonium‐contaminated groundwater in MFCs, that is, ~25–300 mW/m 3 (Adelaja et al, ; Wei et al, ). Groundwater is often contaminated by a variety of organic and inorganic contaminants, for example, 1,4‐dioxane is often found co‐contaminated with chlorinated hydrocarbons (e.g., TCE and TCA; Stefan & Bolton, ; Zhang, Gedalanga, & Mahendra, ). Degradation of chlorinated hydrocarbons has been widely studied on cathodes of bioelectrochemical systems; however, the process generally needs supplying external voltage (Aulenta et al, ; Leitão et al, ; Pous, Balaguer, Colprim, & Puig, ).…”

Field Test of On-Site Treatment of 1,4-Dioxane-Contaminated Groundwater Using <i>Pseudonocardia</i> sp. D17

“…Previous studies have reported that the co-presence of VOCs, such as trichloroethene (TCE) and 1,1-dichloroethene, diminished 1,4-dioxane degradation by several 1,4-dioxanedegrading bacteria by (1) competition between 1,4-dioxane and VOCs on monooxygenases that catalyze the initial oxidation of 1,4-dioxane and also the oxidation of VOCs, (2) repression of degradation gene expression, and (3) toxic effects of themselves or their degradation products [35,36]. It has also been reported that some metals have inhibitory effects on 1,4-dioxane degradation by P. dioxanivorans CB1190 [37].…”