Abstract:

A dilute acetic acid pretreatment technology for corncob was established to remove lignin, convert hemicellulose into xylose and improve the enzymatic hydrolysis yield. The effects of acetic acid concentration, pretreatment temperature and time on pretreatment goal were investigated and the results showed that most of the hemicellulose and partial lignin in the corncob were removed by pretreating with 5% acetic acid. Moreover, the pretreated corncob was easy to be hydrolyzed. Under the optimal condition(pretreatment temperature of 160 ℃, holding time of 60 min, acetic acid concentration of 5% and solid-liquid ratio of 1:8(g:mL), the yield of corncob solid residue was 53.75%, the cellulose retention rate of corncob solid residue could reach 93.17%, and 87.36% of the hemicelluloses and 25.04% of the lignin were removed. Meanwhile, 15.56 g/L xylose was obtained from the pretreatment liquid. The maximum enzymatic hydrolysis yield of pretreated corncob solid could be up to 92.69% within 72 h.

Key words: dilute acetic acid, pretreatment, corncob, xylose concentration, enzymatic hydrolysis yield