UCLA researchers in the Department of Civil and Environmental Engineering have formulated a microbial community that degrades halogenated solvents and their stabilizers in water resources.
Improper storage, discharges, and accidental spills of halogenated solvents and dioxane have led to widespread groundwater contamination. Anaerobic biological reduction is a common remediation strategy for halogenated solvents. However, intermediate products, including known human carcinogens, can accumulate under some conditions. Anaerobic microorganisms capable of biodegrading dioxane have not been isolated. Simultaneous bioremediation of halogenated solvents and dioxane is a challenge because they favor opposing redox conditions. Multiple injections of microorganisms and physical alterations to subsurface oxygen levels increase costs and energy needed to clean up sites contaminated with dioxane and halogenated solvents.
UCLA researchers have formulated a microbial community that simultaneously degrades chlorinated ethenes and dioxane. The mixed microbial culture biodegrades dioxane twice as fast as the pure aerobic culture at higher concentrations of dioxane (15 mg/L) and 20% faster at lower concentrations of dioxane (3 mg/L). Moreover, the microbial community can withstand changing redox conditions and biodegrade both chlorinated ethenes and dioxane. This approach could reduce the cost, energy, and substrates required for in situ bioremediation of chlorinated ethenes and dioxane.