Application of Experimental Design Method for Ethanol Production by Fermentation of Sunflower Seed Hull Hydrolysate Usingpichia Stipitisnrrl-124

The lignocellulosic hydrolysates provide a rich medium for fermentation of sugars into ethanol. The potential use of sunflower seed hull hemicellulose hydrolysate in ethanol fermentation was evaluated by using the Experimental Design method in this study. A 22 Box-Wilson experimental design was used to develop a statistical model. The effects of shaking rate (55–145 rpm) and initial pH (4.6–7.4) on the fermentation of hydrolysate with Pichia stipitis yeast were studied in shaking bath experiments at 30°C. Model equations that represent maximum ethanol concentration Emax and ethanol yield YP/S in terms of shaking rate and pH were developed by using the Design-Expert package program. From response surfaces, optimum variables were calculated numerically by the Design-Expert computer program. Such a procedure provided the optimum values of the parameters with respect to both YP/S and Emax as X1 = 5.89 pH and X2 = 114.6 rpm. The maximum ethanol concentration of 11.04 g/L and ethanol yield of 0.32 were obtained with these optimized parameters.