A Novel Galactoglucomannan Exopolysaccharide Produced by Oil Fermentation with Pseudozyma sp. SY16

Recently, the production of exopolysaccharide from Pseudozyma sp. SY16, which is mannosylerythritol lipid-producing yeast, has been occasionally observed during industrial fermentations. Moreover, exopolysaccharides derived from microbes are in high demand for the production of biopolymers. Therefore, this study aimed to investigate the production and characteristics of the exopolysaccharide produced by this strain. In batch fermentations with this strain, the maximum production yield of exopolysaccharide (5.8 g/L) was obtained under olive oil supplementation as a carbon source with culture conditions of 30°C, pH 8.0, and 600 rpm. Through a series of liquid chromatography steps, the exopolysaccharide was successfully purified, and its emulsifying activity was demonstrated. In addition, two-dimensional nuclear magnetic resonance analysis revealed that the exopolysaccharide is a galactoglucomannan with a novel and unique structure, consisting of galactose, glucose, and mannose in the ratio of 1:5:3.