Figure 4: Morphology of biofilms grown under ALI (A-C) and LLI
(D-F) interfaces: A) and D), representative 3D reconstruction of z-stack
CLSM images B) and E) are 3D projected and orthoclase views of z-stacks
obtained from the CLSM images. The live bacteria were stained with SYTO9
(green), and dead bacteria were stained red-fluorescent propidium
iodide. C) and F) are representative SEM images of PAO1 biofilms showing
the mushroom-shaped aggregates, the upper right corner is magnified
’mushroom-shape’ aggregates.
During biofilm formation, both live and dead bacteria are encased within
the EPS matrix. The CLSM images (Fig.4) show a distinct qualitative
difference between ALI and LLI biofilms in terms of the amount of live
and dead cell. More specifically, biofilm grown on ALI had a higher
ratio of living bacteria than the biofilm formed at LLI (Fig. 5). This
result corroborates with our previous results in Fig. 3, showing that
biofilms formed at LLI were more susceptible to the physical disturbance
compared to ALI cultured biofilm, leaving more bacteria on the membrane
for ALI model biofilm.