The relationship between the fermentation parameters pH, DO and the concentrations of glucose, biomass and the ergosterol content of Saccharomyces cerevisiae in different fed-batch methods are discussed. Different fed-batch methods including constant feed rate fed-batch, constant glucose concentration fed-batch, exponential fed-batch, DO-control exponential fed-batch, pulse fed-batch and DO-control pulse fed-batch are compared. DO-control pulse fed-batch was an effective method for the production of ergosterol, the concentration of which reached 1064 mg/l, 20% higher than in the other fermentations. (C) 2003 Elsevier Science Ltd. All rights reserved.