Utilization of sweetwater as a cost-effective carbon source for sophorolipids production by Starmerella bombicola (ATCC 22214)

Biosurfactants are microbially synthesized surfactants that are environmental friendly due to low toxicity. Sophorolipid is one of the simplest biosurfactants with well-defined structure produced by Starmerella bombicola(ATCC 22214) on glucose and vegetable oil as the carbon source. The raw material cost accounts for 10-30% of the overall cost. Glycerol is readily available from a commercial fat-splitting process as sweetwater at a very low cost. Sophorolipids was synthesized using glycerol and sweetwater as a cost-effective carbon source. The glycerol was further replaced with sweetwater as a source of glycerol. Optimum glycerol concentration was 15% w/v with 10% w/v sunflower oil, giving 6.6 g/L of sophorolipids. The crude sophorolipid contains two major components; both of them were lactonic sophorolipids as analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC), liquid chromatography-mass spectroscopy (LC-MS), and nuclear magnetic resonance ((1)H-NMR).