Assessing the Complementarity of Rhamnolipid and Surfactin Biosurfactants in Stabilizing the Skin-Care Oil-In-Water Nanoemulsions

This research investigates the compatibility of two diverse classes of microbial-derived biosurfactants, namely, surfactin and rhamnolipid, in formulating stable nanoemulsion for skin-care cosmetic applications. By utilizing a high-energy approach, a stable nanoemulsion characterized by a 170 nm droplet diameter and a polydispersity index (PDI) of 0.178 was formulated based on the optimal composition identified using hierarchical cluster analysis of 20 nanoemulsion samples. The comprehensive stress tests on these formulations, such as adjustments in pH, centrifugation, heating, and the addition of salts, demonstrated their robustness against these demanding conditions in skin care applications. Additionally, their antimicrobial and antioxidant properties were found to be comparable with a single microbial surfactant system. These findings contribute to the development of cosmetic and other application-oriented nanoemulsions using mixed biosurfactants.