Review on production, downstream processing and characterization of microbial pullulan.

Pullulan, one of the commercially important microbial exopolysaccharides, is produced by the yeast like fungus Aureobasidium pullulans. It is non-mutagenic, non-toxic, non-hygroscopic, tasteless, odorless, water soluble and edible polymer. Owing to its excellent film forming properties, and typical rheological properties, it is extensively used in diverse industrial applications that include food, agriculture, textiles, cosmetics and pharmaceuticals. In the recent past, there has been growing interest to produce pullulan from low cost substrates in order to bring down cost of pullulan. The cost, productivity and properties of pullulan are highly influenced by the selection of raw material (upstream processing), type of fermentation & fermentation conditions (bioprocessing) and product recovery steps (downstream processing). In addition, both upstream and bioprocessing also affect the rheological, thermal and physical properties of the product. The present review discusses the literature on upstream processing, bioprocessing, product recovery and applications of pullulan.