OPTIMIZATION OF THE SIMULTANEOUS SACCHARIFICATION AND FERMENTATION PROCESS USING THERMOTOLERANT YEASTS

Different treatments to improve the thermotolerance of fermenting yeas ts for simultaneous ethanol saccharification and fermentation process of cellulosic materials have been examined. Yeasts of the genera Sacch aromyces and Kluyveromyces were tested for growth and fermentation at progressively higher temperatures in the range of 4247-degrees-C. The best results were obtained with K. marxianus LG, which was then submit ted to different treatments in order to achieve thermotolerant clones. A total of 35 new clones were obtained that dramatically improved the SSF of 10% Solka-floc substrate at 45-degrees-C when compared to the original strain, some with ethanol concentrations as high as 33 g/L.