Improvement of bacterial cellulose production by addition of agar in a jar fermentor

Bacterial cellulose (BC) was produced by Acetobacter xylinum BPR 2001 and its acetan nonproducing mutant EP1 in corn steep liquor-fructose medium in a 10-l jar fermentor supplemented with different agar concentrations ranging from 0% to 1.0% (w/v). The BC productivity of the two strains was increased by adding agar. The maximum BC production of BPR 2001 at an agar concentration of 0.4% was 12.8 g/l compared with 8 g/l without agar. The mutant EP1 produced 11.6 g/l of BC at an agar concentration of 0.6%, while only 5.5 g/l was produced in the control. Enhanced productivity is associated with an increase in viscosity of the culture, dispersion of BC pellets, and number of free cells due to agar addition, suggesting that acetan produced by BPR 2001 has a critical role in enhanced BC production.