Mössbauer study of bacterial iron reduction of magnetiteтезисы доклада

Дата последнего поиска статьи во внешних источниках: 18 марта 2016 г.

Работа с тезисами доклада


[1] Mössbauer study of bacterial iron reduction of magnetite / N. I. Chistyakova, A. A. Shapkin, A. V. Antonova et al. // International Conference on the Applications of the Mossbauer Effect ICAME 2015 - Book of Abstracts. — Hamburg, Germany, 2015. — P. 248–248. Dissimilatory iron-reducing bacteria get energy through reductive transformations of ferric iron in different compounds. Processes of bacterial iron reduction of magnetite were researched. Magnetite is an iron oxide which is well spread in sedimentary rocks. It is also an important magnetic mineral that can be received extracellularly through the biomineralization pathway. Such characteristics as biocompatibility, nontoxicity and chemically stability of magnetite nanoparticles widen the range of applications from biomedicine to magneto-electronics. Magnetite was synthesized and then added to a cultivation medium of Geolkalibacter ferrihydriticus (strain Z-0531) [1] for sample obtaining. Sulfur and acetate were added to the medium in some experiments. Moreover, the growth of bacterium in the presence of natural magnetite was examined. Mössbauer spectra were measured at room temperature and at T=81K. The spectra were fitted by Zeeman sextets of many-state superparamagnetic relaxation model and quadrupole doublets using the program SpectrRelax [2]. Studies of bacterium growth in the presence of synthetic magnetite and acetate in the medium showed, that new phases had appeared in the reduction process. Besides, it was revealed that atoms of sulfur did not assist in in the bacterial iron reduction. For the verification of the hypothesis of the charge disproportionation reactions in the molecules of synthetic magnetite several passages were made. In the initial passages the reduction of Fe3+ was observed. It is due to the presence of extra electron donor, but not to the charge disproportionation reactions as assumed. The reduction of Fe3+ was found in the experiments in the presence of natural magnetite in the cultivation medium of Geolkalibacterl ferrihydriticus (strain Z-0531). New phases that contain atoms of Fe2+, as well as Fe3+ appear during the growth in such conditions.

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