An original flocculant-producing strain of C8 isolated from soil
were stored in our laboratory. Before irradiation the original
strains were cultured in a beef-protein fluid medium at 35 C with
a shaking frequency of 125 rpm for 10 h. Samples were placed in a
centrifuge at 4000 rpm for 5 min, then washed three times with
sterilized, distilled water. The concentrations of bacterial suspensions
were modulated to 107 cfu/mL. A 0.3 mL bacterial suspension
which was made of normal saline containing glycerol in concentration
of 10% was placed on a 34 mm diameter Petri dish and then
dried at room temperature.