Department of Civil and Environmental Engineering, Rice University, Houston, TX, USA.
Water Res. 2010 May;44(9):2894-900. doi: 10.1016/j.watres.2010.02.007. Epub 2010 Feb 10.
1,4-Dioxane biodegradation was investigated in microcosms prepared with groundwater and soil from an impacted site in Alaska. In addition to natural attenuation conditions (i.e., no amendments), the following treatments were tested: (a) biostimulation by addition of 1-butanol (a readily available auxiliary substrate) and inorganic nutrients; and (b) bioaugmentation with Pseudonocardia dioxanivorans CB1190, a well-characterized dioxane-degrading bacterium, or with Pseudonocardia antarctica DVS 5a1, a bacterium isolated from Antarctica. Biostimulation enhanced the degradation of 50 mg L(-1) dioxane by indigenous microorganisms (about 0.01 mg dioxane d(-1) mg protein(-1)) at both 4 and 14 degrees C, with a simultaneous increase in biomass. A more pronounced enhancement was observed through bioaugmentation. Microcosms with 50 mg L(-1) initial dioxane (representing source-zone contamination) and augmented with CB1190 degraded dioxane fastest (0.16 +/- 0.04 mg dioxane d(-1) mg protein(-1)) at 14 degrees C, and the degradation rate decreased dramatically at 4 degrees C (0.021 +/- 0.007 mg dioxane d(-1) mg protein(-1)). In contrast, microcosms with DVS 5a1 degraded dioxane at similar rates at 4 degrees C and 14 degrees C (0.018 +/- 0.004 and 0.015 +/- 0.006 mg dioxane d(-1) mg protein(-1), respectively). DVS 5a1 outperformed CB1190 when the initial dioxane concentration was low (500 microg L(-1), which is representative of the leading edge of plumes). This indicates differences in competitive advantages of these two strains. Natural attenuation microcosms also showed significant degradation over 6 months when the initial dioxane concentration was 500 microg L(-1). This is the first study to report the potential for dioxane bioremediation and natural attenuation of contaminated groundwater in sensitive cold-weather ecosystems such as the Arctic.
1,4-二恶烷的生物降解在微宇宙中进行，微宇宙的制备材料是来自阿拉斯加污染场地的地下水和土壤。除了自然衰减条件（即不添加任何添加剂）外，还测试了以下处理方法：（a）添加 1-丁醇（一种易得的辅助基质）和无机营养物质进行生物刺激；（b）用 Pseudonocardia dioxanivorans CB1190 （一种特征明确的 1,4-二恶烷降解细菌）或从南极洲分离出的 Pseudonocardia antarctica DVS 5a1 进行生物增强。生物刺激增强了土著微生物对 50mg/L 1,4-二恶烷的降解（4°C 和 14°C 时，约为 0.01mg 二恶烷 d-1 mg 蛋白-1），同时增加了生物量。通过生物增强可以观察到更明显的增强。含有 50mg/L 初始 1,4-二恶烷（代表源区污染）并经 CB1190 增强的微宇宙在 14°C 时降解 1,4-二恶烷最快（0.16+/-0.04mg 二恶烷 d-1 mg 蛋白-1），而在 4°C 时降解速度急剧下降（0.021+/-0.007mg 二恶烷 d-1 mg 蛋白-1）。相比之下，DVS 5a1 微宇宙在 4°C 和 14°C 时以相似的速度降解 1,4-二恶烷（分别为 0.018+/-0.004 和 0.015+/-0.006mg 二恶烷 d-1 mg 蛋白-1）。当初始 1,4-二恶烷浓度较低（500μg/L，代表羽流前缘）时，DVS 5a1 的表现优于 CB1190。这表明这两种菌株的竞争优势存在差异。当初始 1,4-二恶烷浓度为 500μg/L 时，自然衰减微宇宙在 6 个月内也表现出显著的降解。这是第一项报道在北极等敏感寒冷天气生态系统中 1,4-二恶烷生物修复和污染地下水自然衰减潜力的研究。
