Bacterial cellulose-gelatin film from microbial synthesis by Acetobacter xylinum

Abstract

Based on the advantageous and unique properties of bacterial cellulose (BC) and gelatin, those substances have many medical applications. In this study, the bacterial cellulose-gelatin (BCG) composite films were developed by two different preparation methods, (i) supplementation of gelatin during the BC biosynthesis by culture of acetobacter xylinum (Biosyn) and (ii) impregnation of BC films with gelatin aqueous solution, and subsequently cross-linking them with tannic acid (Impreg). The films obtained by both techniques were then characterized for physical and biological properties. It was found that the BC film was rather thin; however, after addition of 7 and 10% w/v of gelatin in the culture medium, the fibrils of the biosyn-BCG films became thicker. The FTIR result indicated the intermolecular interaction between BC and gelatin. Some properties of biosyn-BCG films were different from the BC film. For examples, the water absorption capacity was improved whereas, the crystallinity index and mechanical properties were relatively decreased, without significant changes in water vapor and oxygen transmission. In case of modification of BC film by means of impreg method, the cross-linked gelatin molecules were precipitated on the BC fibrils. The FTIR result indicated the weak intermolecular interaction between BC and gelatin was detected. Consequently, the mechanical properties, water absorption capacity, crystallinity index, water vapor and oxygen transmission rate of Impreg-BCG films had no significant difference from those of the BC film. Nevertheless, only impreg-BCG films showed antimicrobial activity against the growth of staphylococcus aureus. Additionally, BC-gelatin film had no cytotoxic activity against vero cells.