FIGURE 10.

Biofilm formation of B. subtilis 9407(WT) and ΔsrfAB with or without adding exogenous surfactin. WT and ΔsrfAB were grown in MSgg medium for 72 h at 25°C in 12-well microtiter plates and images were taken. WT formed wrinkly floating pellicles at the liquid-air interface of liquid cultures in MSgg. ΔsrfAB formed thinner pellicles. The biofilm formation of ΔsrfAB was restored by adding 2 μL of the commercial surfactin (10 μg/mL).