ABSTRACT
Many prokaryotic and eukaryotic microorganisms can grow on compounds that are poorly soluble in water and often are associated with the production of surface-active compounds or biosurfactants. Biosurfactants comprise a diverse group of chemical structures with amphiphilic character. Generally, the lipophilic parts of their molecules consist of long-chain fatty acids, hydroxyl fatty acids, or α-alkyl-β-hydroxyl fatty acids, while the hydrophilic moieties can be carbohydrates, amino acids, cyclic peptides, phosphates, carboxylic acids, or alcohols. Biosurfactants can be categorized in ve groups regarding their chemical composition: glycolipids, lipopeptides, phospholipids, fatty acids, and polymeric biosurfactants. Biosurfactants can also be grouped into two categories: low-molecular-mass compounds that lower surface and interfacial tension and high-molecular-mass compounds that bind tightly to surfaces (Rosenberg and Ron 1999).
