Behaviour of Biosurfactant Iturin A at Liquid-Liquid Interface

Abstract

Surfactants are surface active agents generally amphiphilic in nature containing a hydrophilic head and a hydrophobic tail. These compounds provide wetting to inorganic and organic contaminants and result in their removal. These compounds are popularly used in soap and detergent industry 1 . Increasing environmental awareness has resulted in an interest in ecofriendly biosurfactants produced by microorganisms. These biosurfactants are a group of structurally diverse surface active substances amphiphilic in nature [2][3][4] . The hydrophilic polar head may consist of mono/oligopolysaccharide or a peptide/protein or glycolipid or lipopeptide or polymer and the hydrophobic moiety consists of a saturated or unsaturated fatty acid or fatty alcohol (Fig. 1). Biosurfactants increase the surface area of hydrophobic, water insoluble substances. Biosurfactants are also excellent emulsifiers, foaming and dispersing agents like conventional surfactants. Further, they possess many advantages, for example, they are environment friendly, biodegradable, less toxic and non hazardous [5][6][7] . They have better foaming properties and higher selectivity. Biosurfactants are active at extreme temperatures, pH 8 and salinity. An important advantage of biosurfactants is that they can be produced from industrial wastes and from by-products 9 . Some biosurfactants can also self aggregate forming a hydrophobic core that helps solubilize and internalize hydrophobic impurities like oil,