抄録
1,4-Dioxane is a cyclic ether mainly utilized in various chemical and pharmaceutical industries as solvent and reactant. Due to its toxic and persistent nature, 1,4-dioxane is a serious pollutant in the aquatic environment. Although 1,4-dioxane is quite recalcitrant to biodegradation, recent researches have shown 1,4-dioxane biodegradation as a sole carbon and energy source or by co-metabolism with tetrahydrofuran (THF). This study isolated and characterized THF-degrading bacteria to develop a biological process of 1,4-dioxane-containing wastewater treatment. Among five THF-degrading bacteria that were isolated, strain T1 from landfill soil and strains T3 and T5 from activated sludge showed stable co-metabolic degradation of 100 mg/L of 1,4-dioxane when coexisting with 100 mg/L of THF. Strains T1 and T5, identified as Rhodococcus ruber, were further characterized. Both strains could utilize a wide range of carbon sources, and grow at 15 - 35°C and pH 6 - 8. They demonstrated to have inducible THF degrading enzymes, and degraded up to 400 mg/L of THF as a growth substrate although they could not mineralize it. The optimum THF/1,4-dioxane ratios for the co-metabolic 1,4-dioxane degradation by strains T1 and T5 were determined to be 2 to 4. Our results would be useful for the development of biological 1,4-dioxane-containing wastewater treatment system.
