A bacterium that could produce a gelatinous cellulosic pellicle in the presence of more than 2% acetic acid was isolated as a contaminant in a continuous surface culture for acetic acid production using Acetobacter aceti. The bacterium was identified as a strain belonging to Acetobacter xylinum and designated as strain DA. The production of cellulose in a static culture of the strain increased about 4-fold as a result of adding 20 g acetic acid per liter of the glucose medium, The enhancement vias specific to acetic acid among the organic acids tested, and was not due to a shift of pH. The cellulose pellicle produced was characterized by a higher water-holding capacity, about 2-fold that of Acetobacter pasteurianus. In a serial transfer culture, the cellulose production by the strain was better in reproducibility than A. pasteurianus.