On static cultivation, Acetobacter xylinum synthesizes bacterial cellulose (BC) that has a gel-like fibril network with inappropriate orientation at the air/liquid interface. This can be easily molded into desired shapes and sizes during synthesis. Here, we report a simple technique to synthesize tubular BC (BC-TS) gel with proper fibril orientation. We found that culturing BC in oxygen-permeable silicone tubes with inner diameter < 8 mm yields a BC-TS gel of the desired length, inner diameter, and thickness with uniaxially oriented fibrils. The fibrils are oriented along the longitudinal axis of the silicone tube, independent of gravity, oxygen availability, and the morphology of the inner surface of the silicone tube but dependent on the curvature of the silicone tube. The degree of orientation (Delta n) of the BC-TS fibrils, as revealed by their birefringence, increases with decrease in the inner diameter of the silicone tube. BC-TS with a uniaxially oriented fibril structure has excellent mechanical properties and holds promise for use as a microvessel or soft tissue material in medical and pharmaceutical applications. (c) 2008 Elsevier Ltd. All rights reserved.