| Project/Area Number |
17360437
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Recycling engineering
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
KONISHI Yasuhiro Osaka Prefecture University, School of Engineering, Professor (90167403)
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| Co-Investigator(Kenkyū-buntansha) |
NOMURA Toshiyuki Osaka Prefecture University, School of Engineering, Associate Professor (00285305)
NAGAMINE Shinsuke Kyoto University, School of Engineering, Assistant Professor (30335583)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥16,770,000 (Direct Cost: ¥15,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2007: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2006: ¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 2005: ¥6,200,000 (Direct Cost: ¥6,200,000)
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| Keywords | Urban mine / Waste recycling / Noble metals / Bioreductive deposition / Biomineralization / Nanoparticles / Metal-ion reducing bacteria / Environmental biotechnology / リサイクル / Shewanella algae / 金属還元細菌 |
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| Research Abstract |
An environmentally friendly method using the metal ion-reducing bacteria Shewanella algae and Shewanella oneidensis was proposed to reduce and deposit noble metal ions (Pt (IV), Pd (II), Au (III) ) in aqueous solutions. Microbial reduction and deposition of noble metal nanoparticles on the bacterial cells were achieved within 30 min at room temperature and neutral pH 7 using resting cells of the bacteria, when either lactate or H_2 was provided as the electron donor. Speciation of noble metal in bacterial cells by X-ray Absorption Near-Edge Spectroscopy (XANES) showed that soluble metal ions were rapidly reduced to insoluble metal in the bacterial cells. Transmission electron microscopy (TEM) of thin sections of bacterial cells revealed that the biogenic noble metal nanoparticles of 5-10 nm were located in the periplasmic space a preferable, cell surface location for easy recovery of biogenic nanoparticles.
Fast bioreductive deposition of gold nanoparticles was also achieved even at the extremes of pH 2 and 10 using resting cells of S. algae in the presence of H_2 as the electron donor. At pH 2.8, gold nanoparticles of 15-200 nm in size were deposited on the bacterial cells, and the biogenic nanoparticles exhibited a variety of shapes that included triangles. At a solution pH of 2.0, gold nanoparticles about 20 nm in size were deposited intracellularly, and larger gold particles approximately 350 nm in size were deposited entracellularly. The solution pH was an important factor in controlling the morphology of the biogenic gold particles and the location of gold deposition. Furthermore, the bioreductive deposition of gold was a fast process in the presence of Cu(II) ions. We strongly believe that the biomineralization of noble metals by the metal ion-reducing bacteria is extremely attractive method for recovering noble metals from electronic scrap leachates in urbane mine.
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