Van Nostrand Joy D, Wu Wei-Min, Wu Liyou, Deng Ye, Carley Jack, Carroll Sue, He Zhili, Gu Baohua, Luo Jian, Criddle Craig S, Watson David B, Jardine Philip M, Marsh Terence L, Tiedje James M, Hazen Terry C, Zhou Jizhong
Institute for Environmental Genomics, University of Oklahoma, Norman, OK 73019, USA.
Environ Microbiol. 2009 Oct;11(10):2611-26. doi: 10.1111/j.1462-2920.2009.01986.x. Epub 2009 Jul 14.
A pilot-scale system was established for in situ biostimulation of U(VI) reduction by ethanol addition at the US Department of Energy's (DOE's) Field Research Center (Oak Ridge, TN). After achieving U(VI) reduction, stability of the bioreduced U(IV) was evaluated under conditions of (i) resting (no ethanol injection), (ii) reoxidation by introducing dissolved oxygen (DO), and (iii) reinjection of ethanol. GeoChip, a functional gene array with probes for N, S and C cycling, metal resistance and contaminant degradation genes, was used for monitoring groundwater microbial communities. High diversity of all major functional groups was observed during all experimental phases. The microbial community was extremely responsive to ethanol, showing a substantial change in community structure with increased gene number and diversity after ethanol injections resumed. While gene numbers showed considerable variations, the relative abundance (i.e. percentage of each gene category) of most gene groups changed little. During the reoxidation period, U(VI) increased, suggesting reoxidation of reduced U(IV). However, when introduction of DO was stopped, U(VI) reduction resumed and returned to pre-reoxidation levels. These findings suggest that the community in this system can be stimulated and that the ability to reduce U(VI) can be maintained by the addition of electron donors. This biostimulation approach may potentially offer an effective means for the bioremediation of U(VI)-contaminated sites.
在美国能源部（DOE）的田纳西州橡树岭现场研究中心，建立了一个中试规模的系统，通过添加乙醇对U(VI)还原进行原位生物刺激。在实现U(VI)还原后，在以下条件下评估生物还原U(IV)的稳定性：（i）静止状态（不注入乙醇），（ii）通过引入溶解氧（DO）进行再氧化，以及（iii）重新注入乙醇。GeoChip是一种功能基因阵列，带有用于氮、硫和碳循环、金属抗性和污染物降解基因的探针，用于监测地下水微生物群落。在所有实验阶段都观察到所有主要功能组的高度多样性。微生物群落对乙醇极为敏感，在恢复注入乙醇后，随着基因数量和多样性的增加，群落结构发生了显著变化。虽然基因数量显示出相当大的变化，但大多数基因组的相对丰度（即每个基因类别的百分比）变化很小。在再氧化期间，U(VI)增加，表明还原的U(IV)被再氧化。然而，当停止引入DO时，U(VI)还原恢复并回到再氧化前的水平。这些发现表明，该系统中的群落可以被刺激，并且通过添加电子供体可以维持还原U(VI)的能力。这种生物刺激方法可能为受U(VI)污染场地的生物修复提供一种有效的手段。
