A conventional randomly packed bed reactor of immobilized cells often has several problems which reduce productivity, including plugging and channelling. A new fixed biofilm reactor has been developed to overcome these disadvantages and to increase overall productivity. Kinetic parameters, such as the saturation constant and the apparent maximum specific production rate for the fermentation of glucose, have been determined, and the ethanol tolerance has been examined. The kinetics of the fixed biofilm reactor were compared with those of the continuous stirred tank reactor.