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 ne wly isolated Acetobacter sp. A9 were determined by shaken cultures. The str ain was able to produce cellulose at 25-30 degreesC with a maximum at 30 de greesC, 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 e xtract, 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 cultiva tion, although this strain produced only 2.2 g/l in the standard medium. Th e addition of ethanol to the improved medium enhanced cellulose production: in an improved medium containing 1.4%(v/v) ethanol, cellulose production w as 15.2 g/l, which was about four times higher than that without ethanol. A ddition of ethanol was found to eliminate the spontaneous mutation of Aceto bacter sp. A9.