The efficiency of a bubble-column reactor in the production of biomass from cheese whey has been studied using Trichosporon yeast. For this purpose, a 9-L reactor with a perforated-plate distributor was used. The effect of the aeration rate, height-to-diameter ratio (LID), and pH of the medium on the efficiency of the bubble-column bioreactor was studied. Under optimized conditions, the fermentation of the deproteinized whey in a batch system resulted in the production of 17.3 g L-1 biomass and 86% chemical oxygen demand reduction.