| In this paper, the static culture medium optimization, the cleaner product, the structure analysis, as well as the application in paper making of bacterial cellulose (BC) was studied. Candida sp. Y-7, L. plantarum L-l and the cellulose synthesizing strains A. xylinum X-2 were used to produce BC for three days in the media of sucrose and tea. The fermenting liquor can be mixed into beverage. The effect of the height of fermenting liquor and the surface of gas-liquor area on the BC production was been studied, when the height of 2?cm was preferred. BC was proved by the tests of paper layer chromatography, X-ray diffl~actometiy, solid-state CPIMAS ?C NMR. The highly crystallinity, cellulose æ…³ and I,~ of BC was analyzed primarily. The result of permeability test showed that the diy membrane of BC has the lower gas, but higher vapor transform rate than PVC and PE membrane, and is found to have fine structure. The disintegration method of the wet pellicle of BC and the behavior of reed pulp in papermaking af1~er adding BC were also studied. The tensile strength and bursting strength of reed pulp sheet increased apparently with increase of BC content. This strength increase could be attributed to the increase of bonding sites among pulp fibers by adding BC, which has a microfibrillar structure with veiy high special surface areas. Air permeance is decreased by adding BC. Porosity decrease would be attributed to sheet densification resulted from the fine and fllamentous structure of the BC fibers. Combining the Plackett-Burman design, response surface analysis and II 3 the steepest ascent method, the static culture media of A. xylinum X-2 was optimized. After the original concentration was confinned to be far from the optimum value, the optimum area was found. The BC production in optimum media reached 4.6g/L, and it was improved by one time as great as in original media.
|
PDF Full Text Request