Production, characterization, and properties of sophorolipids from the yeast Candida bombicola using a low-cost fermentative medium.

The yeast Candida bombicola produces biosurfactant with properties akin to those of sophorolipid (SL) group of compounds. In the present work, the yeast was shown to produce 63.7 g l(-1) SL when grown on a cheap fermentative medium containing sugarcane molasses, yeast extract, urea, and soybean oil. The partially purified SL was characterized and confirmed by Fourier-transform infrared (FT-IR) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) and liquid chromatography-mass spectroscopy (LC-MS) analysis. The critical micelle concentration (CMC) and minimum surface tension of the produced SL in aqueous solution were found to be 59.43 mg l(-1) and 34.15 m Nm(-1), respectively. The emulsification activity and stability with kerosene oil and organic solvents viz. xylene, benzene, and hexadecane were also tested using the produced SL, which yielded better results compared to those reported in the literature.