CARB 91 |
| The changes in residual sugars, pH values and output of bacterial cellulose (BC) in Acetobacter xylinum static cultivations were investigated by using various carbon sources and initial pH values. In addition, the cellulose's physical properties were characterized. The results indicated that among four carbon sources, the highest BC yield was obtained using mannitol. The optimal initial pH for getting the highest yield was 4.5, while bacteria grew well at pH 4-6. Scanning electron microscope images showed that the length and width of A. xylinum is about 2 µm and 0.8 µm. Diameter distribution of BC ranges from 10 to 80 nm, among which 80% distributes between 20 and 50 nm and the range of 30-40 nm was most. Fourier transform infrared spectroscopy demonstrated the characteristic IR bands of the BC glucan. Thermo-gravimetric analysis indicated that thermal decomposition temperature is 342.9°C and the percentage weight loss of cellulose was found to be 72.26% at 622.2°C. One gram of wet BC membrane contained 130-210 g water, which indicated the containing water ratio of BC was morn than 99%. One gram of dry BC membrane could absorb 3.1-5.0 g water. |
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General Posters
6:00 PM-8:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Carbohydrate Chemistry |