Culture conditions in a jar fermentor for bacterial cellulose (BC) production from A. xylinum BPR2001 were optimized by statistical analysis using Box-Behnken design. Response surface methodology was used to predict the levels of the factors, fructose (X1), corn steep liquor (CSL) (X2), dissolved oxygen (DO) (X3), and agar concentration (X4). Total 27 experimental runs by combination of each factor were carried out in a 10-L jar fermentor, and a three-dimensional response surface was generated to determine the effect of the factors and to find out the optimum concentration of each factor for maximum BC production and BC yield. The fructose and agar concentration highly influenced the BC production and BC yield. However, the optimum conditions according to changes in CSL and DO concentrations were predicted at almost central values of tested ranges. The predicted results showed that BC production was 14.3 g/L under the condition of 4.99% fructose, 2.85% CSL, 28.33% DO, and 0.38% agar concentration. On the other hand, BC yield was predicted in 0.34 g/g under the condition of 3.63% fructose, 2.90% CSL, 31.14% DO, and 0.42% agar concentration. Under optimized culture conditions, improvement of BC production and BC yield were experimentally confirmed, which increased 76% and 57%, respectively, compared to BC production and BC yield before optimizing the culture conditions.

Batch and fed-batch fermentations for bacterial cellulose (BC) production using molasses as a carbon source by Acetobacter xylinum BPR2001 were carried out in a jar fermentor. For improvement of BC production, molasses was subjected to H2SO4-heat treatment. The maximum BC concentration by this treated molasses increased 76%, and the specific growth rate increased 2-fold compared with that by untreated molasses. In batch fermentation, when the initial sugar concentrations of H2SO4-heat-treated molasses were varied from 20 to 70 g/L, the highest value of maximum BC concentration of 5.3 g/L was observed at 20 g/L. BC production in intermittent fed-batch (IFB) fermentation was conducted referring to the data in batch fermentation, and the highest BC production of 7.82 g/L was obtained when 0.2 L of molasses medium was added five times. When continuous fed-batch (CFB) fermentations were conducted, maximum BC concentration was obtained with a feeding rate of 6.3 g-sugar/h, which was derived from the optimal IFB experiment.

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Bacterial cellulose (BC) production by Acetobacter xylinum subsp. sucrofermentans BPR2001 using molasses medium was carried out in a jar fermentor. When molasses was subjected to H(2)SO(4)-heat treatment, the maximum BC concentration increased to 76% more than that achieved using untreated molasses, and the specific growth rate increased 2-fold. When the initial sugar concentrations in the H(2)SO(4)-heat treated molasses were varied from 23 g/l to 72 g/l, BC concentration, production rate, and yield were maximum at sugar concentrations of 23 g/l and 37 g/l, and production of by-products, such as polysaccharides and CO(2), was lower than at sugar concentrations of 48 g/l and 72 g/l, indicating that maintaining a lower molasses concentration is essential for efficient BC production in jar fermentors, this being due mainly to the complex nature of molasses. Molasses has a clear advantage over pure sugars as a carbon source from an economic viewpoint.

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