Enhanced enzyme saccharification of Sawtooth Oak shell using dilute alkali pretreatment

This study examined the suitability of Sawtooth Oak (Quercus acutissima) shell waste as feedstock for bioethanol production for the first time. The impacts of varying parameters of dilute alkali pretreatment (temperature, time, and alkalinity) on enzymatic saccharification of oak shell were investigated. Results showed that the combination of 2% NaOH/121 °C (15 psi)/60 min achieved the highest delignification (39.34%) as well as the highest sugar release (426.36 mg/g pretreated material). In addition, optimal combination of 20 FPU cellulase, 20 CBU β-glucosidase and 1.5 FXU xylanase released total sugar yield that peaked at 653 mg/g pretreated material (613 mg glucose and 40 mg xylose). The maximum sugar recovered from the holocellulose fraction was 494.5 mg/g oak shell. This represents a conversion efficiency approaching 78.8% based on monomeric sugar recovery.