Rhamnolipid surfactants: an update on the general aspects of these remarkable biomolecules.

Pseudomonas strains are able to biosynthesize rhamnose-containing surfactants also known as rhamnolipids. These surface-active compounds are reviewed with respect to chemical structure, properties, biosynthesis, and physiological role, focusing on their production and the use of low-cost substrates such as wastes from food industries as alternative carbon sources. The use of inexpensive raw materials such as agroindustrial wastes is an attractive strategy to reduce the production costs associated with biosurfactant production and, at same time, contribute to the reduction of environmental impact generated by the discard of residues, and the treatment costs. Carbohydrate-rich substrates generated low rhamnolipid levels, whereas oils and lipid-rich wastes have shown excellent potential as alternative carbon sources.