A growing suite of Gene-Trac® tests now include targets for the metabolic biodegradation of 1,4-dioxane. Gene-Trac® 1,4-Dioxane is based on two functional genes (dxmB and aldH) identified in the laboratory of Dr. Shaily Mahendra (UCLA) that are active in critical steps of the aerobic 1,4-dioxane degradation pathway. Figure 1 is a simplified degradation pathway for 1,4-dioxane. The multicomponent dioxane monooxygenase (DXMO) enzyme, includes the Beta subunit gene (dxmB). The DXMO enzyme performs the initial hydroxylation step which is followed by spontaneous cleavage of the 1,4 -dioxane ring. The aldehyde dehydrogenase ALDH (aka. aldH) is important in degrading intermediates in the pathway prior to mineralization to C02.
Pseudonocardia dioxyaminovorans CB1190 contains both dxmB and aldH, and therefore, Gene-Trac® 1,4-Dioxane can be used to identify and quantify this organism. Amongst a number of gene targets tested, the dxmB/aldH tests were most strongly associated with organisms capable of 1,4-dioxane degradation activity1 and can be used to determine if a site is a good candidate for monitored natural attenuation (MNA), biostimulation (e.g., oxygen addition) or if bioaugmentation with a 1,4-dioxane degrading culture would be beneficial (see 1,4-Dioxane Bioremediation Update-this issue).
For more information on Gene-Trac® 1,4-Dioxane or molecular tests for other compound classes contact Phil Dennis (firstname.lastname@example.org) toll free 1-866-251-1747 or direct 519-515-0836.
1 Gedalanga, Phillip B, Peerapong Pornwongthong, Rebecca Mora, Sheau-Yun Dora Chiang, Brett Baldwin, Dora Ogles, Shaily Mahendra. Identification of Biomarker Genes To Predict Biodegradation of 1,4-Dioxane. Applied and Environmental Microbiology 80(10) p. 3209–3218.