Novel activated carbon (AC) derived from bacterial cellulose (BC-AC) was produced by phosphoric acid activation at a carbonization temperature of 500 degrees C. BC-AC possesses mesoporous structures of 2.3 nm in diameter, porosity of 1.0 cm(3)/g and surface area of 1734 m(2)/g with high thermal stability between 100 and 500 degrees C. BC-AC could be used as an effective adsorbent for removing methylene blue (MB) from aqueous solutions with the maximum adsorption capacity of 505.8 mg/g. BC-AC presented physisorption and the adsorption of MB was most likely to be a monolayer adsorption. The Redlich-Peterson model displayed the best fit with the experimental data.