Figure 8.

Photo image of the culture solution of P. aeruginosa cultured in the Cooper’s medium without addition of ferrous sulfate for 3 days. After 3 days cultivation, the foam generation by P. aeruginosa was observed on the surface of the culture solution which contained the oxygen nanobubbles and the carbon dioxide nanobubbles whereas it was not observed on the surface of the culture solution which did not contain the nanobubbles. The foam was the most obviously generated in the carbon dioxide nanobubbles medium, suggesting the carbon dioxide nanobubbles has action for activating P. aeruginosa even under low ferrous ion concentration condition.