Switchgrass (Panicum virgatum) was subjected to hydrothermolysis pretreatment and then used to study the effect of enzyme loading and temperature in a simultaneous saccharification and fermentation (SSF) with the thermotolerant yeast strain Kluyveromyces marxianus IMB3 at 8% solid loading. Various loadings of Accellerase 1500 between 0.1 and 1.1 mL g(-1) glucan were tested in SSF at 45 °C (activity of enzyme was 82.2 FPU mL(-1)). The optimum enzyme loading was 0.7 mL g(-1) glucan based on the six different enzyme loadings tested. SSFs were performed at 37, 41 and 45 °C with an enzyme loading of 0.7 mL g(-1) glucan. The highest ethanol concentration of 22.5 g L(-1) was obtained after 168 h with SSF at 45 °C, which was equivalent to 86% yield. Four different batch and fed-batch strategies were evaluated using a total solid loading of 12% (dry basis). About 32 g L(-1) ethanol was produced with the four strategies, which was equivalent to 82% yield.
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