Biological tailoring of novel sophorolipid molecules and their derivatives

A sophorolipid (SL) is a kind of glycolipid surfactant that has been much studied due to its excellent surface activity and physiological properties. However, the mixed structure of SLs and expensive separation costs have limited their application in advanced industries. Developing a tailored strategy to produce targeted SLs, with specific physicochemical properties, for direct application in various industries like agriculture, cleaning, and medicine, has become one of the main objectives of SL biological production. In this review, different characteristics of various SLs with various structures are classified in detail. The classification corresponds to their specific applications in different industries. Microorganisms for the production of specific SLs are also summarized, with emphasis on the metabolism pathways and regulation mechanisms. Strategies applied for SL biological tailoring, including selection of fermenting substrates, fermentation process optimization, metabolic engineering and downstream separation, are comprehensively reviewed.