Figure 1.

Agar plates for isolating IOB and liquid culture experiments for screening IOB that can grow under high-iodideconcentration conditions. (a) The inoculated solid culture medium which consisted of the marine broth, agar, potassium iodide and starch after incubation for a week at 30 °C. The colour of the culture medium around the colonies of IOB became purple because of the iodine-starch reaction; colonies of IOB can therefore be easily found. (b) The inoculated liquid culture solution including the marine broth, potassium iodide and starch after incubation of colonies of IOB isolated from the solid medium shown in (a) for 30 days at 30 °C. The colour of the culture solution became purple because of the iodine-starch reaction, whereas the colour of the negative control (without inoculation of IOB) did not change.