Dilute Acid Pretreatment of Barley Straw and Its Saccharification and Fermentation

Abstract

In this study, the optimization of the major factors for efficient dilute acid pretreatment (DAP) of Korean barley straw was conducted by response surface method (RSM). In addition, saccharification of the optimized pretreated barley straw as well as fermentation of solubilized hemicellulose and enzymatic hydrolysates was performed for bioethanol production. The factors optimized by RSM were concentration of sulfuric acid, reaction time and temperature. Optimization experiments were carried out within the scope of 0.16 similar to 1.84% sulfuric acid, 10 similar to 20 min of reaction time, and 116 similar to 183 degrees C of temperature using a statistical program, and optimal conditions (1.16% of sulfuric acid, 16.9 min of reaction time, and 150 degrees C) were determined based on reliable statistical indicators. The predicted value at stationary point and the experimental value were 81.38 and 80.66%, respectively. Saccharification was performed at 50 degrees C using Celluclast (cellulase) and Novozyme 188 (beta-glucosidase) as biocatalysts in an enzyme loading test. Conversion of the saccharification process was approximately 65%. In addition, fermentation of glucose after saccharification and solubilization of xylose solution by DAP were performed using Saccharomyces cerevisiae and Pichia stipitis at 30 degrees C and 200 rpm for 12 h.