Investigation on the film-forming properties of lab fermenter scale produced scleroglucans from Sclerotium rolfsii ATCC 201126

Abstract

The film-forming capacity of the biopolymer scleroglucan produced on the lab fermenter scale by Sclerotium rolfsii ATCC 201126 was studied. The effect of a freeze-thawing process on the physical properties of scleroglucan films was investigated with hydrogels of three different scleroglucan samples. Films were made from 1% (w/w) scleroglucan hydrogels using 2% (w/w) glycerol as plasticizer by applying two different protocols: (1) a room-temperature drying method and, (2) a freeze-thawing cyclic process (prior to the application of room-temperature drying). The obtained materials were characterized by physical studies including swelling, water vapor transmission, and environmental scanning electron microscopy. Based on the results obtained, when eight freezing-thawing cycles were applied during scleroglucan film preparation, a reinforcement of the structure was achieved pointing to an increase in the number of crosslinking points by H-bonding. All exopolysaccharides produced by S. rolfsii ATCC 201126 at lab fermenter scale showed a general promising behavior for the preparation of reinforced films, opening new perspectives for their potential use in either controlled release systems or the formulation of additive-complemented films for specific applications.