Magnetic properties of magnetite synthesized by Magnetospirillum magnetotacticum MS-1 cultured with different concentrations of ferric iron.
OBJECTIVE
To clarify the effect of Fe(3+) concentration on magnetite formation, Magnetospirillum magnetotacticum MS-1 was cultured at various initial concentrations of Fe(3+) and the yield and magnetic properties of the cells were investigated.


RESULTS
Although total cell yields (g/l) were not dependent on the initial concentration of Fe(3+) (0-68 µM) in the growth medium, the percentage of magnetic cells increased as the initial Fe(3+) concentration increased. The coercivity (H c) and saturation magnetization (M s) of dried MS-1 cells increased and the blocking temperature (T B) decreased as the initial Fe(3+) concentration increased. These values are similar to those reported previously. The Verwey transition temperature (T V) was almost identical for all initial Fe(3+) concentrations (95-97 K), except for medium without added Fe(3+) (0 µM; 88 K).


CONCLUSIONS
Fe(3+) concentration strongly affects the magnetic properties of MS-1 cells, especially in the lower concentration range, suggesting that the Fe(3+) concentration should be considered when evaluating the magnetic properties of MS-1 cells.
Division of Engineering for Composite Function, Muroran Institute of Technology, Muroran, 050-8585, Japan. 11094501@mmm.muroran-it.ac.jp.
Yiriletu
Division of Engineering for Composite Function, Muroran Institute of Technology, Muroran, 050-8585, Japan. iwasat@mmm.muroran-it.ac.jp.|Center of Environmental Science and Disaster Mitigation for Advanced Research, Muroran Institute of Technology, Muroran, 050-8585, Japan. iwasat@mmm.muroran-it.ac.jp.
Tatsuo
T
Iwasa
D003470:Culture Media / Q000737:chemistry; D052203:Ferrosoferric Oxide / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008280:Magnetics; D042201:Magnetospirillum / Q000378:metabolism*
D003470:Culture Media; D007501:Iron; D052203:Ferrosoferric Oxide
Ferric iron; Magnetic properties; Magnetosome; Magnetospirillum magnetotacticum; Magnetotactic bacteria; Nanoparticles