COMPARING PERFORMANCE OF Saccharomyces cerevisiae AND Kluyveromyces marxianus ON SSF PROCESS USING HYDROTHERMALLY PRETREATED SUGARCANE STRAW
Saccharomyces cerevisiae and Kluyveromyces marxianus were used as fermenting microorganism during the simultaneous saccharification and fermentation (SSF) of hydrothermally pretreated sugarcane straw. A pre-saccharification (PS) step prior to SSF process was carried out for 12h at 50oC and pH 4.8, with solid load of 15.0 % (msolid/msolution) and 20 FPU/gcellulose. After PS, the temperature was reduced and the yeast was inoculated (5 g/L). Then, the SSF process was performed for 48h. Different temperatures were evaluated during SSF assays: 34 and 40 oC for S. cerevisiae, and 40 and 45 oC for K. marxianus. Four fermentation parameters were assessed: ethanol concentration, volumetric ethanol productivity, relative and overall ethanol yields. The results demonstrated that both microorganisms exhibited their best results at 40 oC. However, S. cerevisiae showed better performance than K. marxianus, indicating that its use is promising for SSF process from lignocellulosic feedstocks, even not being a thermotolerant yeast.