Community and functional stability in a working bioreactor degrading 1,4-dioxane at the Lowry Landfill Superfund Site

As an environmental contaminant, 1,4-dioxane poses risks for water quality and human health. Used as a solvent and chemical stabilizer in a variety of manufacturing and industrial applications, microbiological methods of detoxification and mitigation are of interest. The degradation of 1,4-dioxane by the bacterium <i>Pseudonocardia</i> spp. is the best understood example; however, these studies are largely based on single isolate, bench-scale, or <i>in silico</i> experiments. Consequently, a knowledge gap exists on bacterial degradation of 1,4-dioxane at environmentally relevant concentrations using functioning remediation technologies at scale. This study addresses this gap directly by describing microbial taxa, enzymes, and potential horizontal gene transfer mechanisms associated with an active treatment plant located on a 1,4-dioxane-impacted U.S. Environmental Protection Agency (EPA) superfund site. As 1,4-dioxane contamination gains more attention, these findings may prove useful for future facilities aiming to promote and optimize removal by biodegradation.