Nata-de-coco, a bacterial cellulose product, which is usually prepared by Acetobacter xylinum grown in mature coconut water, is a quite popular snack in Vietnam and other countries. This research was carried out to obtain pure Acetobacter strains that can produce high cellulose and to investigate the effect of fermenting conditions on cellulose production. Total aerobic microorganisms in four nata fermenting media, collected from local producers in Ben Tre and Vinh Long provinces, Vietnam, were in the range of 8.79-9.14 log cells/mL. Eight strains of Acetobacter sp. were isolated and identified by several biochemical and physiological tests. Acetobacter sp. strain N was selected as the best cellulose producing bacterium. Mature coconut water that incubated 60 h before fermentation and initial bacterial density of inoculum at 6 log cells/mL gave the highest yield (213.87 g cellulose/300 mL fermented mature coconut water). The addition of glucose into the medium up to 5°Brix was also increased the cellulose production (233.15 g/300 mL). Furthermore, the addition of both (NH₄)₂HPO₄ and (NH₄)₂SO₄ or only (NH₄)₂HPO₄ gave higher cellulose yields, 248.23 and 247.70 g cellulose were obtained from 300 mL mature coconut water, respectively.