Tuning surface-active properties of bio-surfactant sophorolipids by varying fatty-acid chain lengths

Sophorolipids are a kind of glycolipid-based bio-surfactant, and some known yeasts can produce them by utilizing plant oil at elevated glucose. In spite of a high production yield, sophorolipids have a limited industrial application, due to their narrow range of HLB (hydrophile - lipophile balance) value. These molecules have regained the attention of researchers and industrialists due to their surface properties and versatile applicability in herbal medicine and cosmetics. The bioactivity and surface properties of sophorolipids are mainly governed by chain length and type of the fatty acid. Therefore, the present study was designed to produce and characterize sophorolipids with varying fatty acid chain lengths. Surface-properties like critical micelle concentration of produced sophorolipids were varying from 43 to 62 (dyne/cm). Foamability, dispersion power, and detergence were found to be higher for short chained fatty acids than the longer ones. Cleaning ability of sophorolipid for FLUX coated PCB was found to be better than the chemical surfactants. Biodegradation rates of the sophorolipids were found to be higher than of the linear alkylbenzene sulfonate (LAS) at room temperature as well as 4 oC. These results showed that the properties of sophorolipids can be tuned by varying the chain’s properties of fatty acids, and it may be possible to customize the properties of sophorolipids for specific industrial applications.