Effect of acid and alkali composite pretreatment and enzyme concentration on hydrolysis efficiency of lignocellulose from dregs of decoction

In order to study the effect of acid and alkali composite pretreatment on the hydrolysis efficiency of dregs lignocellulose,and the feasibility of conversion of dregs cellulose into ethanol,dregs from boiling water extraction of decoction were used as raw material.The dregs were pretreated by a two-stage process for delignification with alkali and peracetic acid(PAA),and were digested in different reaction systems by cellulase.Compared with untreated dregs,the glucose concentration from alkali-PAA pretreated dregs after enzymolysis increased by 3 to 4 times.Increasing the density of substrate and enzyme in the reaction system could remarkably enhance the sugar level without increasing total enzyme amount.83 — 116 mg/mL substrate and 5.8 U/mL enzyme in the reaction system could guarantee the production of glucose over 12 mg/mL.Glucose yield from pretreated salvia dregs,licorice dregs and mixed dregs after hydrolysis for 60 h were 29.07 g/kg,49.31 g/kg,52.83 g/kg,respectively.Pretreatment could significantly improve enzymatic hydrolysis.Glucose yield of dregs was mainly determined by their cellulose content,and was not closely related with dregs type.