Optimization of fermentation conditions for the production of bacterial cellulose by a newly isolated Acetobacter sp A9 in shaking cultures

The optimum fermentation conditions for the production of cellulose by a newly isolated Acetobacter sp. A9 were determined by shaken cultures. The strain was able to produce cellulose at 25-30 degreesC with a maximum at 30 degreesC, Cellulose production occurred at pH 4.5-7.5 with a maximum at pH 6.5. The improved medium composition was 4% (w/v) glucose, 0.1% (w/v) yeast extract, 0.7% (w/v) polypeptone and 0.8% (w/v) Na2HPO4. 12H(2)O. Under these culture conditions, 3.8 g/l cellulose was produced after 7 days of cultivation, although this strain produced only 2.2 g/l in the standard medium. The addition of ethanol to the improved medium enhanced cellulose production: in an improved medium containing 1.4%(v/v) ethanol, cellulose production was 15.2 g/l, which was about four times higher than that without ethanol. Addition of ethanol was found to eliminate the spontaneous mutation of Acetobacter sp. A9.