Resumo

JIMENEZ ISLAS, Donaji; MEDINA MORENO, Sergio A.  e  GRACIDA RODRIGUEZ, Jorge Noel. Biosurfactant properties, applications and production: a review. Rev. Int. Contam. Ambient [online]. 2010, vol.26, n.1, pp.65-84. ISSN 0188-4999.

Surfactants are amphiphilic molecules containing both hydrophilic and hydrophobic parts; these substances are located at the fluid-fluid interface with different degrees of polarity from oil-water or air-water interfaces. The properties of surfactants are characterized principally by four parameters: critical micelle concentration (CMC), aggregation number (n_a), hydrophilic-lipophilic balance (HLB) and cloud point (CP). These parameters are indicative of the potential of the surfactant as an emulsifier and surface-active agent and determine their application, mainly in industry and the environment. Surfactants are synthesized chemically or biologically, in which case they are called biosurfactants. Although an extensive number of microorganisms are capable of synthesizing biosurfactants, they are mainly produced by bacteria. Biosurfactants make up a series of compounds whose structure may be relatively simple such as rhamnolipids, whose structures have mono- and disaccharides joined by glycosidic bonds to hydroxylated carboxylic acids, or more complex such as emulsán, a polymeric biosurfactant with monomeric units of heteropolysaccharides bound to lipids. Biosurfactants have advantages over chemical surfactants due to their compatibility with the environment, low toxicity and biodegradability. However, the principal disadvantage is their high production cost in some cases. In this paper the chemical and microbiological properties of surfactants and biosurfactants are described as well as biosurfactant applications, principally in the bioremediation field. The effect of the main process variables on the production of biosurfactants is also discussed, particularly of rhamnolipids from Pseudomonas aeruginosa.

Palavras-chave : biosurfactants; Pseudomonas aeruginosa; rhamnolipids; surface tension.