PROCESS ENGINEERING OF HIGH-ETHANOL-TOLERANCE YEAST FOR THE MANUFACTURE OF ETHANOL

Inhibitory effects of ethanol and glucose on a high-ethanol-tolerance yeast strain (fusion product of Saccharomyces diastaticus and Saccharo myces uvarum) having high osmotic and ethanol tolerance were studied i n batch cultures. A model incorporating both substrate and product inh ibition was developed that represented the experimental data quite wel l. By performing fed-batch fermentation, an ethanol concentration of 1 3.3% (w/v) was obtained. The maximum allowable ethanol concentration f or cell growth was predicted to be 129.9 g/L and ethanol-producing cap ability of cells was found to be completely inhibited at 136.4 g/L. On -line monitoring of the fermentation was performed using an ion trap m ass spectrometer and a triple quadrupole mass spectrometer. Preliminar y results are reported.