Saccharomyces cerevisiae cells were immobilized on preformed cellulose beads by adsorption. The fermentation capacity of the immobilized yeast cells was found to be practically independent of the hydrogen ion concentration between pH 3.1 and 6.25. The fermentation capacity was maximal at 30 degrees C. The immobilized yeast cells were used for continuous production of ethanol in a fluidized-bead reactor. The average values characteristic for the process were an ethanol concentration of 41.9 +/- 0.1 g l(-1), a fermentation efficiency of 82.9 +/- 2.1% and a volumetric productivity of 3.94 +/- 0.52 gl(-1) h(-1).