title: Aerobic and anaerobic biosynthesis of nano-selenium for remediation of mercury contaminated soil.
abstract: 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-Se0) under both aerobic and anaerobic conditions. The biogenic nano-Se0converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg0) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg0remediation, probably owing to the release of intracellular nano-Se0from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se0and Hg0. Biosynthesis of nano-Se0both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg0-contaminated surface and subsurface soils, where the redox potential often changes dramatically.
authors.affiliation: 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.
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Daoyong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; College of Environment, Zhejiang University of Technology, Hangzhou 310014, China. Electronic address: xiangliangpan@163.com.
authors.forename: Xiangliang
authors.initials: X
authors.lastname: Pan
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
authors.affiliation: Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Fahad A
authors.initials: FA
authors.lastname: Al-Misned
authors.affiliation: Department of Zoology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; Department of Zoology, Faculty of Life and Earth Science, Rajshahi University Rajshahi 6205, Bangladesh.
authors.forename: M Golam
authors.initials: MG
authors.lastname: Mortuza
authors.affiliation: Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.
authors.forename: Geoffrey Michael
authors.initials: GM
authors.lastname: Gadd
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001420:Bacteria, Aerobic / Q000254:growth & development* / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000254:growth & development* / Q000378:metabolism; D001673:Biodegradation, Environmental; D008628:Mercury; D017669:Mercury Compounds / Q000032:analysis* / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D012643:Selenium; D018036:Selenium Compounds / Q000032:analysis* / Q000737:chemistry; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
chemical_list: D017669:Mercury Compounds; D018036:Selenium Compounds; D012987:Soil; D012989:Soil Pollutants; C032901:mercury-selenium complex; D008628:Mercury; D012643:Selenium
keywords: Bioremediation; Mercury; Metal immobilization; Selenium; Selenium nanoparticles