Microbial 1,4-dioxane metabolic enzymes (SDIMO)

Microbial metabolic enzymes for 1,4-dioxane are a specialized group of bacterial oxygenases, predominantly belonging to the soluble di-iron monooxygenase (SDIMO) family, that catalyze the degradation of the environmental pollutant 1,4-dioxane [1, 7]. These enzymes, such as tetrahydrofuran monooxygenase (THF MO) and propane monooxygenase (PrMO), are responsible for the initial hydroxylation of the dioxane ring, a critical step that enables subsequent ring cleavage and mineralization [4, 5]. They are found in various bacterial genera, including Pseudonocardia, Mycobacterium, and Rhodococcus, and can operate through either direct metabolism or cometabolism with substrates like tetrahydrofuran or propane [8, 10]. Although not therapeutic targets in the context of human medicine, these enzymes are essential for bioremediation strategies aimed at removing 1,4-dioxane, a probable human carcinogen, from contaminated groundwater and industrial wastewater [6, 11]. Researchers use the genes encoding these enzymes, such as dxmA and thmA, as molecular biomarkers to assess the potential for natural attenuation or to monitor the progress of bioaugmentation in the field [7, 13]. The activity of these monooxygenases is susceptible to inhibition by substances like acetylene and certain chlorinated solvents, which can pose challenges for effective bioremediation in complex environmental matrices [9, 11].

Other names

1,4-Dioxane monooxygenaseTetrahydrofuran monooxygenaseTHF monooxygenasePropane monooxygenaseSoluble di-iron monooxygenaseSDIMODioxane monooxygenase (DXMO)

Hydroxylation of the alpha-carbon (C2) of the 1,4-dioxane ring to form 2-hydroxy-1,4-dioxane, followed by ring opening and further oxidation to 2-hydroxyethoxyacetic acid (HEAA) and eventually glyoxylate or carbon dioxide.