A polar and hydrophilic ionic liquid, choline dihydrogen phosphate ([ch][dhp]), has been evaluated here as a medium for a bioelectrocatalytic process for generating cellulosic materials. The [ch][dhp] was mixed with water in proportions that best the competing requirements of solubilization and stabilization of enzymes, solution properties, and process conditions. Fructose dehydrogenase (FDH) and cellobiose dehydrogenase (CDH) were immobilized on gold or carbon nanoparticle-modified electrodes, and their biocatalytic oxidation was detected electrochemically in the hydrated [ch][dhp] (Hy[ch][dhp]). An improvement of the shelf life was found (>3 weeks) of CDH immobilized on the electrode in Hy[ch][dhp]. (C) 2011 Elsevier Ltd. All rights reserved.