The precipitate (biomass pellet) was
resuspended with distilled water in the original volume of culture
broth in order to avoid dilution, washed twice with distilled water
using a vortex (Classic, Velp Scientific, Italy) at 3000 rpm for 5 min,
then it was centrifuged at the same conditions mentioned above to
obtain cell-bound biosurfactant suspended in supernatant.