The CMC was determined by plotting the surface tension as afunction of the biosurfactant concentration. The crude biosurfac-tant (150 mg L−1) was serially diluted in distilled water to infinitedilution (absence of biosurfactant), reaching values close to surfacetension of water (72.8 mN m−1) at 30◦C. The inflection in this graphrepresents the CMC [20].