CALORIMETRIC CONTROL OF FED-BATCH CULTURES OF SACCHAROMYCES-CEREVISIAE

Calorimetry has been used to control the glucose feeding in fed-batch cultures of S. cerevisiae in order to avoid ethanol formation and maintain a fully respiratory metabolism. Comparisons between batch and fed-batch cultivations showed that the former had a much lower growth yield. The growth yields for fed-batch cultivations were more than 30% higher than for batch cultures. However, energy balance calculations showed that a large part of the increase could be explained by the evaporation of ethanol during batch cultivations. When the growth yields obtained from the batch cultures were corrected for the evaporation of ethanol, the increase in growth yield for fed-batch cultures was about 10%.