Enzymatic hydrolysis, simultaneous saccharification and ethanol fermentation of oxalic acid pretreated giant reed (Arundo donax L.)

Giant reed was evaluated for enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) using a commercial cellulase/β-glucosidase and Scheffersomyces (Pichia) stipitis CBS 6054 for ethanol production following dilute-oxalic acid pretreatment. A response surface methodology with two input parameters - severity factor (SF) and oxalic acid concentration (OA) - was employed to optimize both enzymatic hydrolysis and SSF. Xylan content after dilute-OA pretreatment decreased with increasing SF and OA; almost complete hydrolysis was observed when the harsher pretreatment conditions were used. Glucan and lignin content showed an opposite trend with respect to xylan content after dilute-OA pretreatment. Accordingly, enzymatic hydrolysis and ethanol production reached 95% of glucan conversion and 18gl-1 (75.3% of the maximum theoretical ethanol yield), respectively, with the pretreatment condition 4.05 SF and 5% OA w/w.Dilute-OA mediated pretreatment of giant reed followed by coupled saccharification and fermentation can be considered a promising methodology for second generation bioethanol production. © 2013 Elsevier B.V.