A Pseudomonas sp. isolated from soil samples when grown on n-alkanes (C12-C18) or vegetable oil produced two extracellular glycolipids (I and II) with surfactant activity. After puritication by column and TLC, the structure of the two rhamnolipids were elucidated by means of mass spectroscopy and by 1H and 13C NMR spectroscopy. The rhamnolipids reduce remarkably the surface tension and the interfacial tension between aqueous solns. and n-hexadecane and show good emulsifying power, foaming ability, and solubilization effect.

Key words: MASS SPECTROGRAPHY, INTERFACES, EMULSIFICATION, RHAMNOSE, SURFACE TENSION, GLYCOLIPID