Organosolv pretreatment of rice straw for efficient acetone, butanol, and ethanol production
Abstract
Acetone-butanol-ethanol (ABE) was produced from rice straw using a process containing ethanol organosolv pretreatment, enzymatic hydrolysis, and fermentation by Clostridium acetobutylicum bacterium. Pretreatment of the straw with 75% (v/v) aqueous ethanol containing 1% w/w sulfuric acid at 150. °C for 60. min resulted in the highest total sugar concentration of 31. g/L in the enzymatic hydrolysis. However, the highest ABE concentration and productivity (10.5. g/L and 0.20. g/L. h, respectively) were obtained from the straw pretreated at 180. °C for 30. min. Enzymatic hydrolysis of the straw pretreated at 180. °C for 30. min with 5% solid loading resulted in glucose yield of 46.2%, which was then fermented to 80.3. g butanol, 21.1. g acetone, and 22.5. g ethanol, the highest overall yield of ABE production. Thus, the organosolv pretreatment can be applied for efficient production of the solvents from rice straw. © 2013 Elsevier Ltd.