STUDIES ON THE USE OF A THERMOTOLERANT STRAIN OF KLUYVEROMYCES-MARXIANUS IN SIMULTANEOUS SACCHARIFICATION AND ETHANOL FORMATION FROM CELLULOSE

The thermotolerant yeast strain, Kluyveromyces marxianus IMB3, was fou nd to be capable of ethanol production during growth at 45 degrees C o n media containing milled paper and exogenously added commercial cellu lase. At maximum achievable cellulose concentrations in shake-flask cu ltures, ethanol production increased to 6.6 g/l at 45 degrees C, repre senting an overall level of conversion of 21% of the maximum theoretic al yield. Subsequent studies involving variations in added cellulase c oncentrations to the batch systems demonstrated that ethanol yields co uld be increased to 10 g/l at 45 degrees C, which represented 39% of t he maximum theoretical yield. As a result of ethanol production at 45 degrees C in the systems examined, we suggest that the thermotolerant ethanol-producing yeast strain K. marxianus represents a novel candida te for use in simultaneous saccharification and conversion of the resu lting substrates to ethanol.