| Bacterial cellulose(BC), synthesized by some microbes, is a kind of ultra-fine and highly pure fiber. And in comparison with other high plant cellulose in nature, BC displays unique properties, including higher purity, higher crystallinity, higher degree of polymerization, higher water absorption capacity, higher tensile strength, stronger bioadadptability and BC can be decomposed directly in natural environment. BC produced by microorganisms has extensive commercial applications. To date, it has been applied in many field of such as food, medical ,paper etc.A bacterial cellulose-producing strain NUST031 was selected by screening some strains from rotten fruits. The morphological features and physiological and biochemical characteristics of strain are examined and tested by the analysis of quinone. Strain NUST031 was preliminarily identified as Acetobacter aceti subsp. The cellulose-producing strain was mutagenized by ultraviolet rays(UV) and UV-LiCl. It was found that much higher cellulose accumulation was obtained by these mutants. The optimum production condition of BC such as carbon source, nitrogen source and primary pH was determined. As far as strain NUST031 was concerned, the typical dynamics of cellulose synthesis during culture was experimented and measured such as glucose and nitrogen utilization and pH in comparison with product's yield. The structural features of product was preliminarily determined by IR. The intensity of the band at 1047cm-1 indicates C-O vibration. A broad peak around 3365 cm-1was shown for O-H vibration and the band around 900cm" conforms the presense of β ,1-4 linkages. The product of acid hydrolysis was proved to be glucose by GC-MS, thus the results indicated that product was bacterial cellulose. The purity of the cellulose was determined by cellulase hydrolysis. Its degree of purity was 95.6%. The water-holding capacity of BC was 98.03%. It was seen that BC had high water absorption capacity. |
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