Effect of homogeneous and inhomogeneous high magnetic fields on bacterial growth measured under a newly developed superconducting magnet biosystem

A new superconducting magnet biosystem (SBS) was developed which can provide 0.5 to 7 tesla (T) magnetic fields. The aerobic growth of a bacterium, Bacillus subtilis M1113 was investigated under homogeneous 7 T and inhomogeneous 5.2-6.1 T magnetic fields in SBS. In the stationary phase, the cell number under the magnetic field was about 2 times higher than that of a control, indicating that the high magnetic field inhibits the death rate of bacterial cells. A genetically transformed B. Subtilis M1113 (pC112) produced higher concentration of a lipopeptide antibiotic, surfactin, under a high magnetic field, reflecting higher cell numbers under a high magnetic field compared with that in the geomagnetic field.