Microemulsions constructed by a biosurfactant

Abstract

Due to their biodegradability and low toxicity, biosurfactants have been recently attracted much attention. Here, microemulsions (MEs) are constructed by an excellent biosurfactant, surfactin, via low energy emulsification. Rheological properties, kinetic stability, thermodynamic stability, and long-term storage capacity of microemulsions were characterized. The effect of pH and different gelling agents on the phase behavior and the formation of microemulsion-gels was also explored. Results reveal that the MEs show no significant change in droplet size under high-speed centrifugation, providing great kinetic stability, which enables the MEs to maintain their stability under bumpy and rugged transportation conditions. The MEs are thermodynamically stable and can be restored to their original state after experiencing extreme conditions such as high temperature (58℃) or freeze-thawing cycles, facilitating the use of the MEs under extreme conditions and promoting the shelf-life of production. The addition of different gelling agents did not show any significant changes to MEs and not disrupt the formation of the MEs, meaning that the MEs constructed by surfactin are stable and possess antioxidant potential and moisturizing effects.