ABSTRACT
Biosurfactants (BSs) are bio-based surface active amphiphilic molecules synthesised by different classes of bacteria, fungi, and actinomycetes. Among these, glycolipid BSs, which include rhamnolipids, sophorolipids, mannosylerythritol lipids (MELs), trehalose lipids (TLs) and cellobiose lipids (CBLs), are known to exhibit excellent physico-chemical and biological interactions. In this chapter, we will concentrate on the diverse properties, production and applications of MELs, TLs and CBLs. MELs, among all other glycolipids, are reported to be produced at a yield of 165 g/L in continuous culture mode. Cellobiose lipids are occasionally produced as minor components with low yield (16g/L). The TLs are reported to be produced at a maximum yield of 40 g/L utilising n-hexadecane as carbon source (Uchida et al. 1989). All the three glycolipids are also produced from renewable substrates which include agro-industrial wastes, vegetable oils and water soluble sugars. They are also produced from non-renewable water-insoluble hydrocarbons. MELs are widely used as cosmetic ingredient for skin applications. Trehalose lipids are candidates for bioremediation and cellobiose lipids have proved to be efficient antifungal agents. The high yield, mild production conditions, structural diversity, excellent physico-chemical properties and biological interactions of MELs over others have made them to be very promising BSs for applications in food, environment, enhanced oil recovery, pharmaceutical and cosmetic and drug/gene delivery.
