Isolation of an Aureobasidium pullulans polysaccharide that promotes adhesion of blastospores to water-borne paints

A polysaccharide composed of maltotriose units was isolated from a liquid culture of Aureobasidium pullulans (De Bary) Arnaud blastospores incubated for 4 h, by precipitation with tetrahydrofuran on solvent-resistant membranes. The concentration of polysaccharide obtained from the liquid cultures after incubation of approximately 106 spores/mL was estimated to be 2 μg/mL of culture filtrate. This polysaccharide seems to be pullulan, as judged by degradation with pullulanase. Newly harvested blastospores resuspended in water did not adhere to the surface of painted wood. However, suspensions of purified culture extract enhanced the adhesion of newly harvested blastospores to the surface of painted wood. It is therefore concluded that pullulan is released by blastospores and contributes to the adhesion of blastospores to surfaces.