This study aimed to identify a conversion number of celluloses of wide-leaved grass (Pennisetum purpureum Schumach) as the raw production of bioethanol processed through a simultaneous fermentation and a fermentation utilizing the role of Clostridium acetobutylicum. The cellulose of the wide-leaved grass was obtained through both fermentation processes using saccharification and simultaneously fermentation methods. The hydrolysis process during fermentation converted cellulose to glucose and simultaneously converted the glucose to bioethanol utilizing Clostridium acetobutylicum. The result of the research showed that the pH of 6.5 in 10 days with 6% of substrate concentration is an optimal condition. It was obtained 33.30 g ethanol at level 96.24% of 1.00 kg cellulose of wide-leaved grass (Pennisetum pupureum). Finally, in conclusion, wide-leafed grass has the potential to produce cellulose for conversion to bioethanol as a renewable energy source.