Preparation Of Solid Bacterial Cellulose And Research On Their Structure

Bacterial cellulose(BC) is an extracellular product of a microorganism, which was used to protect microorganism itself. It has good biocompatibility. It is a kind of cellulose gel, with high water content, called wet bacterial cellulose. Solid bacterial cellulose was prepared by different ways, making it easier to transport, preservation and applications. It was investigated that processing method(Mechanical stirring and ultrasonic) and an ethanol solvent effected on morphology of bacterial cellulose in the process of drying. Bacterial cellulose aerogel and powder were obtained by physical treatment, ultrasound and homogenates. Its crystal structure was characterized by Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction(XRD). Peak fitting was used to analysis the intermolecular and intramolecular hydrogen bond interactions change. Finally the oil potential antioxidant capacity of the initial bacterial cellulose was explored. Results are as follows:1、In drying system of the bacterial cellulose, the proportion between bacterial cellulose and ethanol determined the morphology of solid bacterial cellulose. When the proportion between bacterial cellulose and ethanol was 16:100 and 20:100(w/v), bacterial cellulose membrane with high content of Iα was prepared;2、Through mechanical mixing and freeze drying, bacterial cellulose aerogels was obtained, which was cellulose Ι;3 、 By the addition of Urea(NA), methylcellulose(MC), carboxymethyl cellulose(CMC), the water absorption and crystallinity of aerogel were decreased;(101) crystal plane was increased. The content of Iα of aerogel with MC and CMC was increased.4、Through physical means – ultrasound, a kind of more lightweight bacterial cellulose aerogel was obtained, which provided a physical way to prepare ultra-lightweight cellulose aerogel;5、Ultrasonic treatment did not change the crystalline type of bacterial cellulose aerogel, also was the cellulose I. The degree of crystallinity was decreased, grain size of(101),(101) and(002) crystal plane were increased; intramolecular hydrogen bond strength of bacterial cellulose aerogel was weakened, the intermolecular hydrogen bond strength was increased; Iα cellulose content was reduced.6、Bacterial cellulose powder was prepared by homogenizing, which had different morphologies. Hydrogen bonds of bacterial cellulose was weaken, the degree of crystallinity was reduced, cellulose crystalline type was still cellulose I, but the content of cellulose Iαwas reduced;7、Preliminary inquiry showed that the bacterial cellulose played a role in delaying the oxidation of fish oil.