| Bacterial cellulose (BC) is also by the name of Microbial Cellulose that is a natural polymer synthesized by bacteria. From the cellulose composition, BC is a linear condensation polymer consisting of D-anhydroglucopyranose units (glucose unit for convenience) joined together byβ-1,4-glycosidic bonds (thus a 1,4-β-D glucan) like plant cellulose. While to physical, chemical and mechanical properties, it displays unique properties including high crystallinity, high water holding capacity, nanofibre-network structure, high tensile strength and elastic modulus. Due to its unusual material properties, BC has recently become a kind of attractive biomedical material that was extensively applied to food, paper, biomedical materials, acoustic diaphragms and so on, in the international researches.Blood vessel materials have been worldwide studied. There are lots of surgerys regarding blood vessel reconstruction every year. Artificial vessels had to be used as a substitute, because of the limited source of bolld vessel, the high prices and the biocompatibility form allogeneic vessel. Many efforts have been being made to look for new substitutes in the past thirty years.Oxygen-permeable silicone tubes are adopted frequently when tubular bacterial cellulose is synthesized by microorganism in static fermentation. But the static fermentation has some limitations and shortage, such as the limitation in the length and thickness of tubular materials, long fermentation cycle, and the stratification phenomenon in static fermentation and so on. According to bacterial strain's breeding property, combining with the excellent feature of dynamic and static, a new sub-static bioreactor for preparation of bacterial cellulose tubular has been designed. An optimization on production of bacterial cellulose and effect of design parameters of bacterial cellulose sub-static bioreactor were studied.This paper investigates the property of tubular material prepared in dynamic fermentation by Acetobacter xylinum. The result showed that the BC of dynamic fermentation was better than static fermnetation. In static fermentation, the tubular material had a structure of layer to layer by SEM inspection, but this phenomena does not exist in the dynamic fermentation. A functional relationship had been found between the moisture content, incubation time and BC strength by testing the tubular material.The property of the dissolution of bacterial cellulose was studied in this research. Few results on dissolution of BC were reported and LiCl/DMAC dissolution system is the main used method. But this method is expensive, and is only limited in lab research. In order to find more efficient and relatively cheap solvents to dissolve BC, the dissolution of BC in ionic liquids 1-allyl-3-methylimidazolium chloride [AMIM]Cl and 1-butyl-3-methylimidazolium chloride [BMIM]Cl were investigated in this study. Different BC types (dry or wet), different dissolution temperature and different types of regenerating reagents for BC regeneration were studied to evaluate the dissolution and regeneration properties of BC. The results showed that freeze-dried BC was more easily dissolved than gel-like wet BC. The maximum solubility was 3% (w/v). The optimal dissolution temperature was determined. When deionized water was used as regenerating reagent, a BC suspension solution was obtained. The BC could be harvested by centrifugation and the ionic liquids could be recovered by rotary evaporation to remove water.The modification of bacterial cellulose by using addition of high molecular substances in static fermentation was studied. The strength of the modified bacterial cellulose prepared by addition four different macromolecule in fermention medium was tested. The result showed that the force of modified bacterial cellulose became stronger than control, because of the bacteriostasis of chitosan, it restrain the growth of the bacteria. The existence of the macromolecules in bacterial cellulose material were proven through TGA and DSC analysis. |
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