*2.2. Isolation of the Biosurfactant*

The biosurfactant was extracted after centrifugation of the fermentation broth at 5000× *g* for 30 min to remove the cells. A 6.0 M HCl solution was added to the supernatant to adjust the pH to 2.0, followed by the addition of a 2:1 (*v*/*v*) solution of CHCl3/CH3OH. After vigorous shaking by hand for 15 min and a phase separation, the organic phase was removed and the operation was repeated two more times. The organic phases were pooled and put on a rotary evaporator under a vacuum at 40 ◦C until the complete evaporation of the solvents and the obtention of the isolated biosurfactant [15]. The extraction procedure allowed the isolation of the biomolecule from the fermented broth and, at the same time, the suppression of any live cells still present in it.
