A comparison of polyssacharides from strains of Aureobasidium pullulans

Production of pullulan by five strains of Aureobasidium pullulans was compared in three media with three carbohydrate sources. Our goal was to screen strains and media to obtain pullulan in maximal yield, purity, and stability. Pullulan yields and properties were strongly affected by strain specificity, but a single medium performed best with most strains. Sucrose was the preferred carbohydrate for all five strains. A “color variant” strain of Aureobasidium, NRRL Y-12974, possibly representing a distinct species, produced a polysaccharide of intermediate molecular weight which was stable during storage at 4°C, heating to 100°C, and high shearing action. This polysaccharide was 70% pullulanase sensitive and contained the least contaminating melanin pigment.