FIG. 4.

TLC analysis of the biosurfactant(s). Partially purified biosurfactant from the wild type (WT), the ΔplcR mutant, or the complemented ΔplcR mutant strain (CM) was run on a silica gel TLC plate and stained with ninhydrin (A) or bromthymol blue (B). The biosurfactant(s) is indicated by the upper arrow. Surfactin (40 μg) was run as a positive control (indicated by the lower arrow). (C) Hemolytic assay. One-hundred-microliter volumes of Tris-HCl buffer, surfactin (5 μg/100 μl buffer), and the biosurfactant of the ΔplcR mutant purified from TLC plates (50 μl/100 μl of buffer) were added to wells of sheep blood agar plates and incubated at 37°C for 48 h. The hemolysis results presented are representative of duplicate experiments.