Optimization and evaluation of alkaline potassium permanganate pretreatment of corncob

• We present a novel and one-step simple approach for corncob pretreatment.
• Alkaline potassium permanganate has an effective delignification of corncob.
• High carbohydrate recovery is obtained from the APP-pretreated corncob residue.
• The yield of reducing sugar from APP-pretreated corncob has increased much.

Alkaline potassium permanganate solution (APP) was applied to the pretreatment of corncob with a simple and effective optimization of APP concentration, reaction time, temperature and solid to liquid ratio (SLR). The optimized pretreatment conditions were at 2% (w/v) potassium permanganate with SLR of 1:10 treating for 6 h at 50 °C. This simple one-step treatment resulted in significant 94.56% of the cellulose and 81.47% of the hemicellulose recoveries and 46.79% of the lignin removal of corncob. The reducing sugar in the hydrolysate from APP-pretreated corncob was 8.39 g/L after 12 h enzymatic hydrolysis, which was 1.44 and 1.29 folds higher than those from raw and acid pretreated corncobs. Physical characteristics, crystallinity and structure of the pretreated corncob were analyzed and assessed by SEM, XRD and FTIR. The APP pretreatment process was novel and enhanced enzymatic hydrolysis of lignocellulose by affecting composition and structural features.