Biological amphiphiles (microbial biosurfactants)

Low- and high-molecular-weight biosurfactants are of great interest because of their physicochemical and biological properties, which can be exploited in oil, food, cosmetic and pharmaceutical industries. As for the general types of microbial amphiphiles, the data accumulated over recent years are adding new interesting molecular structures to well-known compounds. Using new strains and cultivation conditions, positive results were found in basic studies of lowering the surface tension of water (72 mN/m→27 mN/m, cmc: 150 mg/l; rhamnose lipids from Pseudomonas aeruginosa), of size determinations of micelles and vesicles (iturin A, a lipopeptide from Bacillus subtilis), of emulsifying properties, biological activities, as well as of application tests in soil remediation.