Production Of Bacterial Cellulose By Acetobacter Xylinum Fermentation

Bacterial cellulose is produced effectively by some microbes. It's a super microscopic fiber net with high purity. The character of bacterial cellulose is more superior than botanical cellulose. This dissertation is on the producing bacterial cellulose with Acetobacter xylinuml.1812. The fermentation condition of Acetobacter xylinuml.1812 has been optimized . Some physical and chemical characters of bacterial cellulose have been studied.The fermentation condition of Acetobacter xylinuml.1812 has been optimized by single factor and orthogonal experiments including the components of medium and the initial fermentation condition and the fermentation parameters. The fermentation condition is 8% sucrose, 1.6% peptone, 0.2% citric acid, 0.2% Na2HPO4, 0.3% KH2PO4, 0.03% MgSO4, pH 6.8, 30, 7% inoculation amount, agitating culture at 200r/min for 5 days.The fermentation product of Acetobacter xylinuml.1812 was hydrolyzed by acid or cellulase, then it was proved that there was glucose in the hydrolyte by TLC and chromatography mass spectrometry, thereby the product was identified as bacterial cellulose. The purity of bacterial cellulose is 95.4% by determining the glucose's content of the hydrolyte of the cellulose. With infrared absorbing analysis method, it was determined that there were some organic compound radicals which were -OH, CH,-CH2, C-O in the structure of the fermentation product. The result accorded with the structure of standard cellulose. The bit shifts of the carbon of the fermentation product were determined by CP/MAS13CNMR, the result accorded with the 13C standard spectrum too. This bacterial cellulose was proved that it did not include crystal by X-ray diffractometry. The water-holding ratio of the wet membrane of bacterial cellulose is 98.9% by weight method. At last, the wet membrane of bacterial cellulose was determined by dielectric constant and DTA.