Gold Biorecovery from Plating Waste by Magnetotactic Bacterium, <i>Magnetospirillum magneticum</i> AMB-1

Tanaka, Masayoshi; Kawase, Masaya; Tanaka, Tsuyoshi; Matsunaga, Tadashi

doi:10.1557/proc-1169-q03-12

Cited by 4 publications

(1 citation statement)

References 6 publications

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“…We have already investigated the use of magnetotactic bacteria for the biomagnetic recovery of toxic and/or valuable metals and metalloid such as Cd (10,11), Au (12), and Te (13). In these studies, Cd 2ϩ and AuCl 4 Ϫ were mainly adsorbed onto the cell surface (10,12), while the Te oxyanion (TeO 3 2Ϫ ) was reduced and biomineralized as discrete independent elemental Te nanocrystals within the cells, with no incorporation into the magnetite crystals (13). The dual crystallization of tellurium and magnetite by magnetotactic bacteria enabled approximately 70 times more bioaccumulation of the pollutant per cell than cell surface adsorption.…”

Section: Importancementioning

confidence: 99%

Biomagnetic Recovery and Bioaccumulation of Selenium Granules in Magnetotactic Bacteria

Tanaka

Knowles

Brown

et al. 2016

Appl Environ Microbiol

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Using microorganisms to remove waste and/or neutralize pollutants from contaminated water is attracting much attention due to the environmentally friendly nature of this methodology. However, cell recovery remains a bottleneck and a considerable challenge for the development of this process. Magnetotactic bacteria are a unique group of organisms that can be manipulated by an external magnetic field due to the presence of biogenic magnetite crystals formed within their cells. In this study, we demonstrated an account of accumulation and precipitation of amorphous elemental selenium nanoparticles within magnetotactic bacteria alongside and independent of magnetite crystal biomineralization when grown in a medium containing selenium oxyanion (SeO 3 2؊ ). Quantitative analysis shows that magnetotactic bacteria accumulate the largest amount of target molecules (Se) per cell compared with any other previously reported nonferrous metal/metalloid. For example, 2.4 and 174 times more Se is accumulated than Te taken up into cells and Cd 2؉ adsorbed onto the cell surface, respectively. Crucially, the bacteria with high levels of Se accumulation were successfully recovered with an external magnetic field. The biomagnetic recovery and the effective accumulation of target elements demonstrate the potential for application in bioremediation of polluted water. IMPORTANCEThe development of a technique for effective environmental water remediation is urgently required across the globe. A biological remediation process of waste removal and/or neutralization of pollutant from contaminated water using microorganisms has great potential, but cell recovery remains a bottleneck. Magnetotactic bacteria synthesize magnetic particles within their cells, which can be recovered by a magnetic field. Herein, we report an example of accumulation and precipitation of amorphous elemental selenium nanoparticles within magnetotactic bacteria independent of magnetic particle synthesis. The cells were able to accumulate the largest amount of Se compared to other foreign elements. More importantly, the Se-accumulating bacteria were successfully recovered with an external magnetic field. We believe magnetotactic bacteria confer unique advantages of biomagnetic cell recovery and of Se accumulation, providing a new and effective methodology for bioremediation of polluted water.

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