Interest in polymer production by microorganisms has significantly
increased due to its widespread use in various sectors. There are three major classes of
microbial polysaccharides, namely extracellular, intracellular and structural. Of these,
exopolysaccharides are preferred because of their easy isolation and purification and
also because of their high yielding potential in a short time period. Exopolysaccharide
production is reported in a considerable number of fungi, including higher
basidiomycetes, lower filamentous fungi, and yeasts from different ecological niches.
Among these, the exopolysaccharides, botryosphaeran, pullulan, and scleroglucan,
produced by Aureobasidium pullulans, Botryosphaeria, and Sclerotium, respectively,
have been commercially produced and are well known for their applications in diverse
fields. Exopolysaccharide production in fungi mainly depends on the fungal strain
used, the physical conditions used for fermentation, and the medium components used
for the production. Fungal exopolysaccharides are significant primarily because of their
properties such as pseudoplasticity, resistance to salt and thermal degradation, high
viscosity even at diluted concentrations, and high-temperature tolerance. Fungal
polysaccharides have been extensively exploited in various sectors such as petroleum,
bioremediation, food, biomedical, cosmetic, textile, and pharmaceutical.
Keywords: Botryosphaeran, Exopolysacharides, Pullulan, Scleroglucan.
