Fig. 6. The viability of S. cerevisiae upon incubation at pH 5.5 with aqueous solutions of different concentrations of (A) free BRB and (B) BRB-loaded shellac NPs (non-coated with ODTAB) at room temperature up to 6 hours incubation time at pH 5.5. (C)–(H) SEM images of S. cerevisiae whereby (C) and (D) represent the control sample. (E) and (F) S. cerevisiae cells incubated with 0.01 wt% free BRB after 4 hours incubation, (G) and (H) S. cerevisiae incubated with 0.01 wt% BRB-loaded in shellac NPs up to 4 hours. Note that the free BRB is less effective anti-yeast agent than the non-coated shellac NPs with the same concentration of shellac NP-loaded BRB.