Purification and characterization of liposan, a bioemulsifier from Candida lipolytica

Abstract

The inducible water-soluble bioemulsifier liposan was purified from the yeast Candida lipolytica. Th purification procedure included repeated solvent extractions of a concentrated culture filtrate and Affi-Gel concanavalin A affinity chromatography. The procedure yielded a preparation containing a major band (M(r) = 27,600) which stained for protein and carbohydrate upon polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Liposan is composed of approximately 83% carbohydrate and 17% protein. Acid and enzymatic digestions of the emulsifier revealed that the carbohydrate portion is a heteropolysaccharide consisting of glucose, galactose, galactosamine, and galacturonic acid. Liposan effected and stabilized oil-in-water emulsions with a variety of commercial vegetable oils. Emulsification and stabilization properties of liposan were compared to those of a number of commercial emulsifiers and stabilizers.