A Review on Antimicrobial Activity, Anti-Biofilm and Synergistic Effects of Sophorolipids Since Their Discovery

Sophorolipids (SLs) as a kind of glycolipid biosurfactants are secondary metabolites produced by non-pathogenic yeasts and other microorganisms. Structurally, SLs are composed of a disaccharide sophorose which is beta-glycosidically linked to a long fatty acid chain. SLs have broad applications in various areas and many companies are developing SLs products for food, cosmetics, cleaning, personal care, environmental industries, pharmaceutics, and fungicides. Antimicrobial activity, anti-biofilm, and synergistic effect of SLs have been paid more attention since their discovery, especially in recent years. In this review, we reviewed the inhibitory effects of SLs on bacterial and fungal growth and their biofilms formation, and we provided an overview of the synergistic effects of SLs combined with other antimicrobial substances. Furthermore, the antimicrobial mechanisms of SLs action and perspectives on future research for the development of SLs as antimicrobial therapeutics are discussed.