Rhamnolipids: Well-Characterized Glycolipids with Potential Broad Applicability as Biosurfactants

Rhamnolipids are well-studied glycolipids secreted by Pseudomonas aeruginosa that have been found to have excellent surface activity. Already used in various application areas, including environmental, health, food, cosmetic, and oil industries, rhamnolipids are attractive candidates to replace chemically synthesized surfactants because they are derived from a natural source at high purities and have low toxicity levels. Production of rhamnolipids depends on several environmental and nutritional factors, and the highest yield is estimated to be 6 g/L; recent advances in recovery methods have resulted in 99.9% pure rhamnolipids. Rhamnolipids have several beneficial characteristics: they are easily degradable, nontoxic, nonmutagenic, and have the highest surface-tension-reduction index of any surface-tension reducing agent currently in use. They have broad potential applicability across industries. They can also be used in oil-spill management, environmental management, biodegradation and remediation, the uptake of heavy metals and environmental pollutants, and the production of skin-compatible biochemicals for use in cosmetics. Rhamnolipids have applicability as antimicrobial, antifungal, antiviral, anti-algal, and anti-protist agents. In this review, we summarize the production parameters, properties, and industrial potential of rhamnolipids, as the next generation of biosurfactants. © 2014, Mary Ann Liebert, Inc.