Wang Xiaonan, Zhang Daoyong, Pan Xiangliang, Lee Duu-Jong, Al-Misned Fahad A, Mortuza M Golam, Gadd Geoffrey Michael
Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
Chemosphere. 2017 Mar;170:266-273. doi: 10.1016/j.chemosphere.2016.12.020. Epub 2016 Dec 5.
Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se) under both aerobic and anaerobic conditions. The biogenic nano-Se converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg remediation, probably owing to the release of intracellular nano-Se from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se and Hg. Biosynthesis of nano-Se both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg-contaminated surface and subsurface soils, where the redox potential often changes dramatically.
硒（Se）纳米颗粒通常由厌氧菌合成。然而，厌氧细菌不能直接用于受污染表土的生物修复，因为表土通常是有氧的。在本研究中，一种亚硒酸盐还原菌——弗氏柠檬酸杆菌Y9，在有氧和厌氧条件下均表现出较高的亚硒酸盐还原能力，并产生了元素态纳米硒颗粒（纳米硒）。在厌氧和好氧条件下，生物源纳米硒分别将污染土壤中45.8 - 57.1%和39.1 - 48.6%的元素汞（Hg）转化为不溶性硒化汞（HgSe）。添加十二烷基磺酸钠可增强汞的修复效果，这可能是由于细胞内纳米硒从细菌细胞中释放出来用于汞的固定。修复后的反应产物被鉴定为由纳米硒和汞合并形成的非反应性HgSe。因此，无论在好氧还是厌氧条件下进行纳米硒的生物合成，都为汞污染的表层和地下土壤提供了一种通用且经济高效的修复方法，因为这些土壤的氧化还原电位常常会发生显著变化。
