Optimization of the simultaneous saccharification and fermentation process using thermotolerant yeasts

Different treatments to improve the thermotolerance of fermenting yeasts for simultaneous ethanol saccharification and fermentation process of cellulosic materials have been examined. Yeasts of the generaSaccharomyces andKluyveromyces were tested for growth and fermentation at progressively higher temperatures in the range of 42–47°C. The best results were obtained withK. marxianus LG, which was then submitted 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°C when compared to the original strain, some with ethanol concentrations as high as 33 g/L.