Structural and rheological characterization of bacterial cellulose gels obtained from Gluconacetobacter genus

This study explores the structural and rheological properties of bacterial cellulose gels (pellicles) produced by bacteria isolated from several kinds of fruits. The three bacteria isolated were identified as Gluconacetobacter sp. and two strains of Gluconacetobacter hansenii. The obtained pellicles were analyzed by Fourier transform infrared spectroscopy, solid-state C-13 nuclear magnetic resonance, and X-ray diffraction. On the basis of the structural characterization, the I-alpha content was approximately 60%, the extent of crystallization was in the range 57-67%, and the crystal sizes were in the range 5.23-5.68 nm. Morphology of the pellicles was observed by scanning electron microscopy. Rheological properties of the pellicles were evaluated using a rheometer. The widths of cellulose fibers and rheological properties were different among the pellicles produced by the mentioned bacteria. Overall, the results obtained in this study indicated that the rheological properties of the BC pellicles were strongly influenced by the network structure of the cellulose fibers rather than by fiber concentrations. Thus, we obtained useful information related to BC pellicle for both basic research as well as for the determination of their potential for application in industries concerning food, cosmetics, and medicine.