Abstract: The effects of magnetic treatment on the biomass and excreting of exo-polysaccharides(EPS) of Spirulina were studied systematically. It proved that a lower magnetic intensity(≤40kA/m) is good for improving the biomass of Spirulina but the growth rate restrained as magnetic intensity higher than 40kA/m. 24kA/m is the optimum condition for improving the growth rate and the maximum-cell-concentration. The higher the magnetic intensity, the stronger the restraint is when the magnetic intensity is higher than 80kA/m. The growth stops almost when the magnetic intensity is higher than 400kA/m. Although the growth of Spirulina is restrained at the higher intensity magnetic treatment, it could stimulate the excretion of EPS obviously. It was also found that the optimum magnetic effect takes place in logarithmic growth phase.

Key words: Spirulina, cultivation, magnetic field, EPS of Spirulina